Syringe plunger sensing mechanism for a medical injector

ABSTRACT

Embodiments of an injector, syringe, syringe interface, syringe adapter, and piston/plunger assembly for an injector (of contrast medium, for example) are described. Preferably, the syringe is adapted to engage a syringe interface mechanism such that the syringe may be connected to an injector without regard to any particular orientation of the syringe to the injector or to the piston/plunger assembly. The injector piston or drive member includes a sensing pin positioned at a forward end thereof to sense contact with the syringe plunger during advancement of the piston or drive member to contact the plunger. The piston can be advanced automatically upon connection of, for example, the syringe to the injector, or piston advance can be automated to occur after operator initiation. The injector may include or be adapted to accommodate two syringes, which for example provide for simultaneous injection of fluid into separate injection sites on a patient.

BACKGROUND OF THE INVENTION

This invention relates to medical injectors, and syringes, syringeinterfaces, syringe adapters and syringe plungers for use therewith.More particularly, the present invention relates to front-loadingmedical injectors, and syringes, syringe interfaces, syringe plungersand adapters for use with new or existing medical injectors wherein asyringe of special construction is mountable upon and removable from theinjectors by a releasable mechanism.

Medical injectors and syringes for injecting contrast media into apatient for imaging biological structures are known in the art. Forexample, U.S. Pat. No. 4,677,980, issued to D. M. Reilly et al. on Jul.7, 1987, and entitled “Angiographic Injector and Angiographic Syringefor Use Therewith,” which is assigned to the same Assignee as thesubject application, discloses an angiographic injector apparatus. Theapparatus is designed for injecting contrast media into the vascularsystem of an animal, in which syringes are rear-loaded into a pressurejacket of the injector. More specifically, the apparatus comprises arotatable turret which carries a pair of the pressure jackets and whichis rotatable so that when one of the pressure jackets, into which asyringe has been rear-loaded, is in an injection position, the otherpressure jacket is in a position in which an associated syringe can berear-loaded. Subsequently, when injection of contrast media from thefirst syringe is completed, the turret is rotated to move the firstsyringe to an unloading-loading position, with the second pressurejacket and the syringe concurrently being moved into the injectionposition.

In the apparatus disclosed in the '980 patent, a drive member of theangiographic injector can be drivingly connected to, or disconnectedfrom, a plunger of a syringe at any point along the path of travel ofthe syringe plunger by a releasable mechanism. However, for thereleasable mechanism to correctly operate, the syringe plunger must beproperly oriented to mate with the injector piston. Further, duringloading of the syringe on the injector, the syringe must be correctlyaligned within a respective pressure jacket to allow the syringe plungerand the injector piston to connect to and disconnect from each other.

An improved apparatus over the '980 patent apparatus is disclosed inU.S. Pat. No. 5,383,858, issued to D. M. Reilly et al. on Jan. 24, 1995,and entitled “Front-Loading Medical Injector and Syringe for UseTherewith,” which is also assigned to the same Assignee as the presentapplication. In the apparatus described in the '858 patent, the syringeis front-loaded onto, in at least one embodiment, a pressure jacket-lessinjector, overcoming one of the drawbacks of the '980 patent injectorapparatus.

The injector described in the '858 patent has a first release mechanismfor attaching and releasing the syringe from the injector. In addition,the apparatus includes a second release mechanism that engages anddisengages the injector piston from the syringe plunger. Upon rotationof the syringe, the syringe is attached to or released from the injectorand, simultaneously, the plunger is attached to or released from thepiston. The structure disclosed requires that the syringe be installedon the injector in a specific orientation so that the syringe canreleasably engage the injector and, simultaneously, the plunger canreleasably engage the piston. In addition, as with the syringe disclosedin the '980 patent, during assembly the syringe plunger must becorrectly oriented within the syringe.

Another injector apparatus is disclosed in U.S. Pat. No. 5,300,031,issued to C. Neer et al. on Apr. 5, 1994, and entitled “Apparatus forInjecting Fluid into Animals and Disposable Front Loadable SyringeTherefor.” The '031 patent discloses various embodiments of a pressurejacketed injector wherein a syringe is loaded into and removed from aninjector pressure jacket through an opening provided in the front end ofthe pressure jacket. To retain the syringe within the pressure jacket,for example, during an injection operation, the front end of the syringeis locked to the front end of the pressure jacket. To correctly connectthe syringe to the pressure jacket, the syringe may only be insertedinto the pressure jacket in one orientation.

In each example discussed above, the syringe must be connected to theinjector in a specific orientation to assure proper syringe mounting.Proper alignment is required to assure that the syringe may be operatedproperly during a medical imaging procedure. The required orientation,however, hinders rapid attachment and replacement of the syringe. Therequired orientation may also increase the manufacturing assembly costand complexity of the syringe.

Accordingly, while the above injector and syringe apparatuses haveproven effective, a need has arisen for a simpler front-loading medicalinjector. More specifically, to facilitate further the loadingoperation, a need has arisen for a syringe that can be easily connectedto the injector without regard for the specific orientation of thesyringe and/or syringe plunger. In addition, to simplify assembly of thesyringe components, a need has arisen for a syringe with a plunger thatdoes not need to be oriented in a specific relation to the barrel orbase of the syringe. Furthermore, to minimize the time required toprepare an injector for an injection procedure, a need has arisen forinjectors providing automated features and/or improved control features.

SUMMARY OF THE INVENTION

The present invention provides medical injectors, syringe interfaces,syringe adapters, syringe plungers and syringes for use therewith whichaddress the needs that have arisen for a simpler injector and syringesystem. Specifically, the present invention provides, in one aspect, asyringe interface and a mating syringe that cooperate to allow thesyringe to be easily, readily and securely fastened to a medicalinjector. The syringe need not be oriented in any particular mannerbefore being connected to the injector. In addition, the plunger neednot be oriented in any particular manner with respect to the barrel ofthe syringe. The syringe and plunger both are provided with releasemechanisms so that the syringe can be quickly installed on and unloadedfrom the injector and replaced with a new syringe.

To accomplish these objectives, the present invention provides a syringefor engaging an injector. In a preferred embodiment, the syringeincludes a syringe body having a syringe forward end adapted to dispensefluid and a syringe rearward end adapted to engage with the injector. Aplunger or plunger cover is axially reciprocable within the syringebody. A flange member is disposed at the syringe rearward end. Theflange is adapted to engage a flexible ring within a connector mechanismon the injector housing, or on a syringe interface or an adapterconnected to the injector housing. The flange and flex ring combinationprovide for engagement of the syringe to and release of the syringe fromthe injector. Further, the syringe includes one or more members forengaging the flexible ring to permit disengagement of the syringetherefrom.

In an alternate embodiment, the flange member may be disposed at thesyringe forward end and the flexible ring may be disposed on a forwardend of a pressure jacket connected to an injector.

In another embodiment, the syringe includes a syringe body having asyringe forward end adapted to dispense fluid and a syringe rearward endadapted to engage with the injector. A plunger or plunger cover isaxially reciprocable within the syringe body. At least one tab or flangemember (which may be resilient) is disposed at the syringe rearward end.The at least one tab or flange is adapted to engage a wall portion on aninjector, or a syringe interface or an adapter connected to theinjector, when the syringe engages with the injector. The at least onetab or flange provides for engagement of the syringe to and release ofthe syringe from the injector.

In still another embodiment, the syringe includes a syringe body havinga syringe forward end adapted to dispense fluid and a syringe rearwardend adapted to engage with the injector. A plunger is axiallyreciprocable within the syringe body. At least one resilient tab isdisposed at the syringe rearward end. The at least one resilient tab isadapted to engage a wall portion on the injector, or a syringe interfaceor an adapter connected to the injector, when the syringe engages withthe injector. The at least one tab provides for engagement of thesyringe to and release of the syringe from the injector.

In an alternate embodiment, the syringe includes at least two resilienttabs adapted to engage the wall portion of the injector when the syringeengages the injector. In still another embodiment, the syringe includesmore than two tabs that are arranged around its base so that the syringesecurely engages the injector.

The present invention further provides an injector system combining asyringe and an injector. The syringes have the same generalconstructions as described above. The injector includes an interfaceadapted to receive the rearward end of the syringe. In a preferredembodiment, the interface of the injector includes a flexible ring forengaging a flange member disposed on the syringe. In an alternateembodiment, the flexible ring may be disposed on a forward end of apressure jacket connected to the injector, and the flange member may bedisposed on the forward end of the syringe to engage the flexible ring.In another embodiment, the injector includes a forward portion having afirst diameter adapted to receive the syringe rearward end. The injectorinterface also includes a rearward portion having a second diameter,larger than the first diameter, and a ledge disposed between the forwardportion and the rearward portion, joining the forward portion and therearward portion together. The at least one tab on the syringe isadapted to resiliently engage the ledge when the syringe is engaged withthe injector. The interface of the injector further includes a collar,reciprocable within the rearward portion adjacent a wall therein,adapted to urge the at least one tab inwardly to disengage the at leastone tab from the ledge, thereby enabling removal of the syringe from theinjector.

The present invention further provides an injector piston, a syringeplunger assembly and a combined piston/plunger assembly. In a preferredembodiment, the syringe plunger assembly includes a plunger cover and anassociated plunger cover support ring disposed within the syringe. In analternate embodiment, the syringe plunger assembly includes only aplunger cover disposed within the syringe. The injector piston ispreferably shaped to complement the shape of the plunger cover. Inaddition, the injector piston is preferably adapted to push the syringeplunger cover during forward axial movement, without an actualconnection being made therebetween. During retraction of the plunger,however, the injector piston is adapter to connectively engage theplunger or plunger cover.

In one embodiment, the piston/plunger assembly includes a pistonassociated with an injector, a piston sleeve surrounding the piston, acollar connected to one end of the piston sleeve, the collar defining anopening through which the piston extends, a plunger cap connected to thecollar, the plunger cap defining an interior space, a gripper extenderdisposed on an end of the piston within the interior space of theplunger cap, a plurality of slots through a side of the plunger cap, aplurality of grippers disposed through the slots and being engageablewith the gripper extender, and a biasing member in contact with thepiston sleeve. Upon movement of the piston in a direction, the biasingmember biases movement of the piston sleeve to restrict movement in thesame direction to cause the gripper extender to push the plurality ofgrippers through the slots in the plunger cap for engagement with aplunger or rubber cover within a syringe.

In other embodiments, the plunger and piston may be adapted to connecttogether electromechanically or electromagnetically.

Further in accordance with the embodiments set forth above, the presentinvention also provides an adapter for receiving a syringe. The adapterengages with an injector and is disposed between the injector and thesyringe. The adapter includes an adapter forward end adapted to engagethe syringe. In one embodiment, the adapter rearward end has at leastone resilient tab that is adapted to engage with the injector.

The present invention further provides for an adapter assembly. Theadapter assembly includes an adapter and a syringe for use therewith. Ina preferred embodiment, the adapter includes an adapter rearward endcomprising a flange member adapted to engage with a flexible ring of aninjector. In this embodiment, the adapter would allow an injectordesigned according to the present invention to accept conventionalsyringes.

In an alternate embodiment, the adapter may have a rearward endincluding a mechanism allowing it to mate with existing injectors (suchas the injectors disclosed in U.S. Pat. Nos. 4,677,980, 5,383,858 and5,300,031, the disclosures of which are hereby incorporated byreference) and a forward end including a flexible ring or a ledge orshoulder member allowing it to mate with syringes designed according tothe present invention. In this embodiment, the adapter would allowconventional or existing injectors to accept syringes designed accordingto the present invention.

In addition, the present invention provides methods for engaging orinstalling the front-loading syringes and adapters of the presentinvention and/or existing syringes with the front-loading injectors ofthe present invention and/or existing injectors

Furthermore, the present invention provides injectors and injectorsystems having certain automated features that facilitate thepreparation thereof for injection procedures.

The present invention offers many advantages over the prior art. Forexample, the present invention provides a syringe that does not have tobe aligned and/or oriented with respect to an injector for installationthereon. Further, the present invention provides a syringe in whichalignment, either radially or axially, between the plunger and syringeis not required.

Moreover, the piston of the present invention may be designed so that itdoes not permanently engage the plunger. So designed, the plunger actsprimarily as a pusher during the injection operation. Only when theplunger must be retracted, for example, to aspirate fluid into thesyringe, may an engagement mechanism be activated so that the pistonconnects to the plunger. By virtue of this arrangement, the plunger maybe left in any position when the syringe is removed from the injectorsystem.

In another aspect the present invention provides an injector including ahousing and at least one drive member at least partially disposed withinthe housing and operable to engage the plunger of a syringe mounted onthe injector. The injector further includes at least one syringeretaining mechanism associated with the housing that is adapted toreleasably engage the syringe and a first sensing pin positioned at aforward end of the drive member to sense contact with the syringeplunger. The first sensing pin can, for example, be biased in a forwardextended position and forced rearward to impinge upon a sensor whencontact with the syringe plunger is made during advancement of the drivemember.

The injector can further include a sensing system to sense when asyringe or a syringe adapter is attached to the retaining mechanism. Thesensing system can further sense the syringe configuration.

In one embodiment, the drive member automatically moves forward uponconnection of a syringe to the retaining mechanism to engage the syringeplunger (for example, upon connection of the syringe to the retainingmechanism). Preferably, the forward movement of the drive member isstopped upon engagement with the syringe plunger but before the plungeris moved forward.

The injector can further include a second drive member at leastpartially disposed within the housing and operable to engage a plungerof a second syringe. In this embodiment, the injector also includes asecond syringe retaining mechanism associated with the housing andadapted to releasably engage the second syringe. Preferably, a secondsensing pin is positioned at a forward end of the second drive member tosense contact with the second syringe plunger.

The injector can also include a source of a first injection fluid influid connection with the first syringe, and a source of a secondinjection fluid in fluid connection with the second syringe.

The injector can also include a first control unit positioned outside ofa scan room in which an injection procedure takes place and a secondcontrol unit positioned inside the scan room. For example, an injectionprotocol for control of the injection procedure can be entered at thefirst control unit. The first control unit can include a protocol editlock function, which may be activated by the operator once an injectionprotocol has been set. Preferably, a change in injection protocol afteractivation of the protocol edit lock function is associated withdeactivating the lock function. The second control unit preferablyincludes an indicator of the state (for example, activated ordeactivated) of the lock function. In general, the second control unitpreferably includes an indicator of whether an injection protocol setwith the first control unit has been changed.

In one embodiment, the injector has a mode of operation in which thefirst fluid is injected from the first syringe and the second fluid issimultaneously injected from the second syringe into a single injectionsite. Preferably, the injector has three modes of operation including(1) sequential injection of the first fluid from the first syringe andof the second fluid from the second syringe into a single injectionsite; (2) simultaneous injection of the first fluid from the firstsyringe and the second fluid from the second syringe into a singleinjection site; and (3) simultaneous injection of the first fluid fromthe first syringe and the second fluid from the second syringe into twodifferent injection sites.

In another aspect, the present invention provides a method of injectingfluids into a patient to a region of interest within the patient. Themethod preferably including the steps of (1) injecting a first fluidinto a first injection site on the patient suitable to transport thefirst fluid to the region of interest; and (2) injecting a second fluidinto a second injection site on the patient suitable to transport thesecond fluid to the region of interest. The first fluid and the secondfluid can be the same. For example, the first fluid and the second fluidcan be a contrast medium suitable to enhance an image in a medicalscanning procedure.

In a further aspect, the present invention provides an injectorincluding a housing and at least one drive member at least partiallydisposed within the housing and being operable to engage the plunger ofthe syringe. The injector also includes at least one syringe retainingmechanism associated with the housing. The syringe retaining mechanismis adapted to releasably engage the syringe. The injector furthercomprises a first control unit positioned in a control room. The firstcontrol unit includes a protocol edit lock function, which may beactivated by the operator once an injection protocol has been set. Achange in injection protocol after activation of the protocol edit lockfunction is preferably associated with deactivating of the lock function(for example, automatically upon editing the protocol or manually priorto editing the protocol). The injector further includes a second controlunit positioned in a scan room. The second control unit includes anindicator of the state of the lock function.

In still another aspect, the present invention provides an injectorincluding a housing and at least one drive member at least partiallydisposed within the housing. The drive member is operable to engage aplunger of the syringe. The injector also includes at least one syringeretaining mechanism associated with the housing. The syringe retainingmechanism is preferably adapted to releasably engage the syringe. Theinjector also includes a first control unit positioned in a controlroom. The first control unit enables setting of an injection protocol.The injector further includes a second control unit positioned in a scanroom. The second control unit includes an indicator of whether theinjection protocol set with the first control unit has been changed.

The present invention, along with the attributes and attendantadvantages thereof, will best be appreciated and understood in view ofthe following detailed description taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The various embodiments of the present invention are described inconnection with the figures appended hereto, in which:

FIG. 1 is a perspective view of an injector apparatus in accordance withthe present invention, showing an injector housing and a syringe in adisassembled relationship;

FIG. 2 is an enlarged perspective view of the syringe illustrated inFIG. 1, shown connected to a front wall of the injector housing,illustrating how a flange disposed at a rearward end of the syringe mayprevent leaking fluid from entering the injector housing;

FIG. 3 is an enlarged cross-sectional view of the syringe shown in FIGS.1 and 2, illustrating the construction of a forward end of the syringe;

FIG. 4 is a perspective view of another embodiment of the presentinvention, illustrating a syringe and a pressure-jacketed injector in adisassembled relationship;

FIG. 5 is another perspective view of the embodiment illustrated in FIG.4, showing a piston displaced at a more forward position than thatillustrated in FIG. 4;

FIG. 6 is a cross-sectional view of the syringe and housing illustratedin FIGS. 1 and 2, showing the secure connection of the syringe to thefront wall of the injector housing through tabs attached at the rearwardend of the syringe;

FIG. 7 is an enlarged cross-sectional view of the structures enclosed bycircle VII in FIG. 6, showing in greater detail the connection of thesyringe to the front wall of the injector housing;

FIG. 8 is an enlarged perspective view of the tabs illustrated in FIG. 7that are connected to the rearward end of the syringe illustrated inFIG. 1;

FIG. 9 is an enlarged cross-section of an alternate embodiment of tabsattached at the rearward end of a syringe for engagement with a frontwall of an injector, showing essentially the same structures illustratedin FIG. 7;

FIG. 10 is an enlarged perspective view of yet another embodiment of asyringe in accordance with the present invention, illustrating at leastone tab at a base of the syringe for engagement with a ledge defined inan interface of an injector housing;

FIG. 11 is an enlarged perspective view of the syringe illustrated inFIG. 10, showing the at least one tab from the rearward end (or baseside) of the syringe;

FIG. 12 is an enlarged perspective view of another embodiment of asyringe in accordance with the teachings of the present invention,illustrating two tabs at the base of the syringe for engagement with theinjector housing;

FIG. 13 is an enlarged perspective view of the syringe shown in FIG. 12,illustrating the two tabs at the rearward end of the syringe;

FIG. 14 is an enlarged perspective view of still another embodiment of asyringe in accordance with the present invention, illustrating more thantwo tabs at a base of the syringe for engagement with an injectorhousing;

FIG. 15 is an enlarged perspective view of the syringe illustrated inFIG. 14, showing the base end of the syringe with the plurality of tabs;

FIG. 16 is a partial, enlarged perspective view of an alternateembodiment of the tab arrangement illustrated in FIGS. 1 and 8;

FIG. 17 is a cross-sectional view of the tab arrangement illustrated inFIG. 16, taken along line XVII-XVII;

FIG. 18 is a cross-sectional view of the syringe illustrated in FIGS. 14and 15 with a portion of a front wall of an injector housing, showing aledge that is securely engaged by tabs at the base of the syringe, andalso showing a reciprocating collar that disengages the tabs from theledge;

FIG. 19 is a cross-sectional illustration of the embodiment illustratedin FIG. 18, showing the tabs engaging the ledge so that the syringesecurely engages the injector housing;

FIG. 20 is a cross-sectional illustration of the embodiment shown inFIGS. 18 and 19, showing the engagement of the reciprocating collar withthe tabs to disengage them from the ledge of the injector housing;

FIG. 21 is a cross-sectional view of an adapter assembly connected tothe syringe illustrated in FIGS. 14 and 15;

FIG. 22 is a cross-sectional view of an alternate embodiment of theadapter assembly illustrated in FIG. 21, where the adapter includes atabbed opening for engagement with the injector housing;

FIG. 23 is a perspective view of the adapter and syringe illustrated inFIG. 22;

FIG. 24 is another perspective view of the adapter and syringeillustrated in FIG. 22;

FIG. 25 is a cross-sectional view of an embodiment of a plunger andpiston according to the teachings of the present invention, showing anelectromagnetic mechanism that causes the plunger and piston to beattracted to one another during operation of the apparatus;

FIG. 26 is a partial cross-sectional view of another embodiment of aplunger and piston, showing an electromechanical mechanism that causesthe plunger and piston to be releasably attached to one another duringoperation of the apparatus;

FIG. 27 is an enlarged cross-sectional view of the piston and plungerillustrated in FIG. 26, showing the piston engaging the plunger;

FIG. 28 is a cross-sectional view of the combination of the piston andthe plunger shown in FIG. 27, the view taken along line XXVIII-XXVIII,showing two protrusions extended so that the piston engages the plunger;

FIG. 29 is a cross-sectional view of the combination of the piston andthe plunger shown in FIGS. 26-28, with the two protrusions retracted sothat the piston can disengage from the plunger;

FIG. 30 is an enlarged cross-sectional view of a plunger according tothe teachings of the present invention, illustrating the placement of apressure-sensing device in the plunger;

FIG. 31 is an enlarged cross-sectional view of the plunger illustratedin FIG. 30, showing the plunger subjected to a pressure from the fluidcontained in a syringe (not illustrated);

FIG. 32 is a side view illustration of an alternate embodiment of thepresent invention where tabs are added to a syringe cap that engages theend of a pressure jacket;

FIG. 33 is an enlarged cross-sectional view of an alternate embodimentof the apparatus shown in FIG. 7;

FIG. 34 is an enlarged cross-sectional view of the alternate embodimentof the apparatus shown in FIG. 33;

FIG. 35 is a side view illustration of another embodiment of theapparatus that releasably connects the plunger and piston to oneanother;

FIG. 36 is a side view illustration of still another embodiment of theapparatus that releasably connects the plunger and piston to oneanother;

FIG. 37 is an end view illustration of the separable members shown inFIG. 36;

FIG. 38 is a perspective cut-away illustration of a pressure jacketembodiment of the present invention showing the reciprocating collardisposed within the pressure jacket;

FIG. 39 is a cross-sectional view of the pressure jacket embodimentillustrated in FIG. 38, taken along line XXXIX-XXXIX;

FIG. 40A is an exploded, perspective view of another embodiment of afront-loading syringe interface and syringe system in accordance withthe present invention;

FIG. 40B is a perspective view of the system shown in FIG. 40A in aninstalled position;

FIG. 40C is a perspective view of the syringe interface shown in FIG.40A in an open position;

FIG. 41A is an assembled, perspective view of another embodiment of afront-loading syringe interface and syringe system in accordance withthe present invention;

FIG. 41B is a perspective view of the system shown in FIG. 41A in anopen position;

FIG. 41C is a front, perspective view of the syringe interface shown inFIG. 41A in an open position;

FIG. 41D is a rear, perspective view of the syringe interface shown inFIG. 41A in an open position;

FIG. 42A is an assembled, perspective view of an alternate embodiment ofthe embodiment of the front-loading syringe interface and syringe systemshown in FIGS. 41A-41D;

FIG. 42B is a perspective view of the system shown in FIG. 42A in adisengaged position;

FIG. 42C is a front, perspective view of the syringe interface shown inFIG. 42A in a closed position;

FIG. 42D is a plan, perspective view of the syringe interface shown inFIG. 42A in a closed position;

FIG. 43A is an exploded, perspective view of another alternateembodiment of the embodiment of the front-loading syringe interface andsyringe system shown in FIGS. 41A-41D;

FIG. 43B is a perspective view of the syringe interface shown in FIG.43A in a closed position;

FIG. 43C is a side, perspective view of the system shown in FIG. 43A ina first disengaged position;

FIG. 43D is a perspective view of the system shown in FIG. 43A in aninstalled position;

FIG. 43E is a perspective view of the system shown in FIG. 43A in asecond disengaged position;

FIG. 43F is a perspective view of the system shown in FIG. 43A in anopen position for syringe removal;

FIG. 43G is an exploded, perspective view of the system shown in FIG.43A with the syringe interface in an open position;

FIG. 43H is a front, perspective view of the syringe interface shown inFIG. 43A in an open position;

FIG. 431 is a rear, perspective view of the syringe interface shown inFIG. 43A in an open position;

FIG. 44A is a perspective view of a slightly altered version of thesyringe interface shown in FIGS. 43A-43I incorporated in or mounted onan injector head;

FIG. 44B is a rear, perspective view of the syringe interface andinjector head shown in FIG. 44A;

FIG. 45A is a perspective view of a second, slightly altered version ofthe syringe interface shown in FIGS. 43A-43I incorporated in or mountedon an injector head;

FIG. 45B is a rear, perspective view of the syringe interface andinjector head shown in FIG. 45A;

FIG. 46A is an exploded, perspective view of a first preferredembodiment of a front-loading syringe interface and syringe system inaccordance with the present invention;

FIG. 46B is an assembled, perspective view of the syringe interfaceshown in FIG. 46A;

FIG. 46C is a perspective view of the system shown in FIG. 46A in adisengaged position;

FIG. 46D is a perspective view of the system shown in FIG. 46A in aninstalled position;

FIG. 47A is a perspective view of an alternate embodiment of the firstpreferred embodiment of the front-loading syringe interface and syringesystem shown in FIGS. 46A-46D in an installed position;

FIG. 47B is a perspective view of the system shown in FIG. 47A in adisengaged position;

FIG. 47C is an exploded, perspective view of the system shown in FIG.47A;

FIG. 47D is an exploded, perspective view of the syringe interface shownin FIG. 47A;

FIG. 47E is a rear, partially assembled, perspective view of the syringeinterface shown in FIG. 47A;

FIG. 47F is a rear, exploded, perspective view of the syringe interfaceshown in FIG. 47A;

FIG. 48A is an exploded, perspective view of still another embodiment ofa front-loading syringe interface and syringe system in accordance withthe present invention;

FIG. 48B is a perspective view of the system shown in FIG. 48A in adisengaged position;

FIG. 48C is a perspective view of the system shown in FIG. 48A in aninstalled position;

FIG. 49A is an assembled, perspective view of another embodiment of aninjector piston and syringe plunger interface system of the presentinvention;

FIG. 49B is an exploded perspective view of the piston plunger systemshown in FIG. 49A;

FIG. 49C is a perspective view of the piston/plunger system shown inFIG. 49B with the plunger base separated from the plunger cover andassociated with the piston;

FIG. 49D is a perspective of the piston/plunger system shown in FIG. 49Bwith the plunger, including the plunger base and the plunger cover,separated from the piston;

FIG. 49E is a rear, perspective view of the piston/plunger system shownin FIG. 49A in a disengaged position;

FIG. 49F is an exploded, perspective view of the plunger base and theplunger cover shown in FIGS. 49C and 49D;

FIG. 50A is an exploded, perspective view of another embodiment of aninjector piston and syringe plunger interface system of the presentinvention;

FIG. 50B is an enlarged view, partially in cross-section, of the plungerbase and the piston shown in FIG. 50A in an engaged position;

FIG. 51A is an exploded, perspective view of an alternate embodiment ofthe injector piston and syringe plunger interface system shown in FIGS.50A and 50B;

FIG. 51B is a perspective view of the piston/plunger system shown inFIG. 51A with the plunger base separated from the plunger cover andassociated with the piston;

FIG. 51C is an enlarged view, partially in cross-section, of the plungerbase and the piston shown in FIG. 51A in an engaged position;

FIG. 52A is an exploded, perspective view of still another embodiment ofan injector piston and syringe plunger interface system of the presentinvention;

FIG. 52B is an exploded perspective view of the piston/plunger systemshown in FIG. 52A;

FIG. 52C is a rear, perspective view of the piston/plunger system shownin FIG. 52A in a disengaged position;

FIG. 53A is an exploded, perspective view of an alternate embodiment ofthe injector piston and syringe plunger interface systems shown in FIGS.51A-51C and 52A-52C;

FIG. 53B is an enlarged, perspective view of the piston/plunger systemshown in FIG. 53A in a disengaged position;

FIG. 53C is a cross-sectional view of the piston/plunger system shown inFIG. 53A;

FIG. 53D is an exploded, perspective view of the piston/plunger systemshown in FIG. 53A;

FIG. 54A is a perspective view of a current syringe plunger;

FIG. 54B is an exploded, perspective of the plunger shown in FIG. 54A;

FIG. 54C is a perspective view of an embodiment of a syringe plunger ofthe present invention;

FIG. 54D is an exploded, perspective of the plunger shown in FIG. 54C;

FIG. 54E is a perspective view of another embodiment of a syringeplunger of the present invention;

FIG. 54F is an exploded, perspective view of the syringe plunger shownin FIG. 54E;

FIG. 54G is a perspective view of yet another embodiment of the syringeplunger of the present invention;

FIG. 54H is an exploded, perspective view of the syringe plunger shownin FIG. 54G;

FIG. 55 is a side view schematic illustration of a second preferredembodiment of a front-loading syringe interface and syringe system inaccordance with the present invention, illustrating a release mechanismfor connecting a syringe to an injector housing;

FIG. 56 is an exploded, isometric, front view perspective of the syringeinterface and syringe system shown in FIG. 55;

FIG. 57 is an exploded, isometric, rear view perspective of the syringeinterface and syringe system shown in FIG. 56;

FIG. 58 is an exploded, isometric, rear view perspective of a portion ofthe syringe interface and syringe system shown in FIGS. 55-57;

FIG. 59 is an exploded, isometric, rear view perspective of anotherportion of the syringe interface and syringe system shown in FIGS.55-57, showing in detail the rear of a portion of a flex ring and arotating ring of the interface/release mechanism;

FIG. 60 is an isometric, rear view of the syringe interface and syringesystem shown in FIGS. 55-59, detailing the connection of the syringe tothe release mechanism;

FIG. 61 is an exploded, isometric, front view perspective illustrationof the portion of the present invention as shown in FIG. 59, detailingthe front of the rotating ring and a portion of the flex ring thereof,FIG. 62 is a partial, isometric, front view, perspective illustration ofthe rear portion of the syringe of the second preferred embodiment ofthe present invention, detailing the ridge and flange structure thereof;

FIG. 63 is a partial, isometric, rear view, perspective illustration ofthe syringe shown in FIG. 62;

FIG. 64 is an isometric, rear view perspective illustration of the frontplate of the release mechanism of the second preferred embodiment of thepresent invention;

FIG. 65 is an isometric, front view perspective illustration of thefront plate shown in FIG. 64;

FIG. 66 is an isometric, front view perspective illustration of the flexring element of the release mechanism of the second preferred embodimentof the present invention, detailing several aspects thereof;

FIG. 67 is an isometric, rear view perspective illustration of the flexring shown in FIG. 66;

FIG. 68 is an isometric, front view perspective illustration of therotating ring element of the release mechanism of the second preferredembodiment of the present invention, detailing several aspects thereof;

FIG. 69 is an isometric, rear view perspective illustration of therotating ring shown in FIG. 68;

FIG. 70 is an isometric, front view perspective illustration of the rearplate of the second preferred embodiment of the release mechanism of thepresent invention, detailing several aspects thereof;

FIG. 71 is an isometric, rear view perspective illustration of the rearplate shown in FIG. 70;

FIG. 72 is an isometric, front view perspective illustration of thesyringe interface and syringe system of the second preferred embodimentof the present invention;

FIG. 73 is an isometric, rear view perspective illustration of thesyringe interface and syringe system shown in FIG. 72;

FIG. 74 is a cross-sectional schematic illustration of a portion of thesyringe interface/release mechanism of the second preferred embodimentof the present invention before insertion of the syringe into theinterface/release mechanism;

FIG. 75 is a side view, cross-sectional schematic illustration of thesame elements shown in FIG. 74, with the syringe partially inserted intothe interface/release mechanism;

FIG. 76 is a side view, cross-sectional schematic illustration of thesame features of the second preferred embodiment of the presentinvention as shown in FIGS. 74 and 75, in this case illustrating thesyringe after it has been fully inserted into the interface/releasemechanism;

FIG. 77 is an end view, cross-sectional schematic illustration of thesyringe and flex ring elements of the present invention as shown in FIG.76, depicting the engagement of the syringe by the flex ring;

FIG. 78 is an end view, cross-sectional schematic illustration of thesyringe and flex ring of the second preferred embodiment of the presentinvention, depicting the disengagement of the syringe from the flex ringafter rotation of the syringe through a one quarter turn;

FIG. 79 is a perspective illustration of a related art syringe, showingthe efficacy of the flange on the syringe for preventing contrast mediafrom entering the injector housing;

FIG. 80 is an isometric, front view, perspective illustration of a firstpreferred embodiment of the injector piston and syringe plungerinterface system of the present invention;

FIG. 81 is an isometric, rear view perspective illustration of thepiston/plunger assembly depicted in FIG. 80;

FIG. 82 is an exploded, isometric view of the piston/plunger assemblydepicted in FIGS. 80 and 81;

FIG. 83 is an exploded, isometric rear perspective illustration of thefront end of the first preferred embodiment of the piston/plungerassembly of the present invention;

FIG. 84 is an exploded, isometric view of the same features of thepiston/plunger assembly illustrated in FIG. 83, taken from a slightlydifferent angle from the view shown in FIG. 83;

FIG. 85 is an isometric, front view illustration of the piston from thepiston/plunger assembly illustrated in FIGS. 80-82;

FIG. 86 is an isometric, side view illustration of the pistonillustrated in FIG. 85;

FIG. 87 is an isometric, front view illustration of the piston sleeve ofthe piston/plunger assembly shown in FIGS. 80-82;

FIG. 88 is an isometric illustration of the collar element of thepiston/plunger assembly shown in FIGS. 80-82;

FIG. 89 is another isometric view of the collar depicted in FIG. 88;

FIG. 90 is a third isometric view of the collar element depicted in FIG.88;

FIG. 91 is an isometric end view illustration of the gripper expanderelement of the first preferred embodiment of the piston/plunger assemblyof the present invention;

FIG. 92 is a second isometric illustration of the gripper expanderdepicted in FIG. 91;

FIG. 93 is a third isometric illustration of the gripper expanderdepicted in FIGS. 91 and 92;

FIG. 94 is a first isometric illustration of one of the support ringgrippers of the first preferred embodiment of the piston/plungerassembly of the present invention;

FIG. 95 is a second isometric illustration of the support ring grippershown in FIG. 94;

FIG. 96 is another isometric illustration of the support ring grippershown in FIGS. 94 and 95;

FIG. 97 is a first isometric illustration of the plunger cap element ofthe first preferred embodiment of the piston/plunger assembly of thepresent invention;

FIG. 98 is a second isometric illustration of the plunger cap shown inFIG. 97;

FIG. 99 is another isometric illustration of the plunger cap shown inFIGS. 97 and 98;

FIG. 100 is a fourth isometric illustration of the plunger cap elementshown in FIGS. 97-99;

FIG. 101 is a first isometric illustration of the rubber cover sup portring element of the first preferred embodiment of the piston/plungerassembly of the present invention;

FIG. 102 is a second isometric illustration of the rubber cover supportring element shown in FIG. 101;

FIG. 103 is a third isometric illustration of the rubber cover supportring element shown in FIGS. 101 and 102;

FIG. 104 is a fourth isometric illustration of the rubber cover supportring element depicted in FIGS. 101-103;

FIG. 105 is an isometric, side view illustration of the rubber cover ofthe plunger of the first preferred embodiment of the piston/plungerassembly of the present invention;

FIG. 106 is a second isometric illustration of the rubber cover shown inFIG. 105;

FIG. 107 is a side view schematic illustration of a portion of the firstpreferred embodiment of the piston/plunger assembly of the presentinvention, showing the interrelation of the piston, collar, gripperexpander, support ring grippers and plunger cap thereof, theillustration showing the relationship of these elements when at rest orwhen the piston is moved toward the front end of the syringe;

FIG. 108 is a side view schematic illustration of the portion of thepiston/plunger assembly depicted in FIG. 107, in this case showing theinterrelation of the piston, collar, gripper expander, support ringgrippers and plunger cap thereof when the piston is moved/retractedtoward the rear end of the syringe;

FIG. 109 is a side view schematic illustration of a portion of thepiston/plunger assembly and the syringe, showing the interrelation ofthe syringe, rubber cover, support ring grippers, and rubber coversupport ring when the piston is moved/retracted toward the rear end ofthe syringe and the support ring grippers engage the rubber coversupport ring;

FIG. 110 is an isometric illustration of an alternate embodiment of arubber cover for use with a plunger of the present invention;

FIG. 111 is a side view illustration of the rubber cover illustrated inFIG. 110;

FIG. 112 is a top view illustration of the rubber cover illustrated inFIG. 110;

FIG. 113 is a cross-sectional illustration of the rubber cover depictedin FIG. 110;

FIG. 114 is an isometric, exploded illustration of an alternateembodiment of the syringe interface/release mechanism of the presentinvention;

FIG. 115 is an end-view, schematic illustration of another embodiment ofthe syringe interface/release mechanism of the present invention;

FIG. 116 is a cross-sectional illustration of an end portion of thesecond preferred embodiment of the syringe according to the presentinvention;

FIG. 117 is a cross-sectional illustration of an alternate embodiment ofthe syringe shown in FIG. 116;

FIG. 118 is a schematic representation of three embodiments of groovesthat are provided in the rotating ring of the second preferredembodiment of the syringe interface/release mechanism of the presentinvention;

FIG. 119 is an isometric, exploded illustration of another embodiment ofa syringe interface/release mechanism according to the teachings of thepresent invention;

FIG. 120 is an isometric, exploded illustration of still anotherembodiment of a syringe interface/release mechanism according to theteachings of the present invention;

FIG. 121 is a front view illustration of yet another embodiment of asyringe interface/release mechanism according to the teachings of thepresent invention;

FIG. 122 is a side view illustration of the syringe interface/releasemechanism illustrated in FIG. 121;

FIG. 123 is an isometric, front view perspective of an alternateembodiment of the syringe shown in FIGS. 55-57;

FIG. 124 is an exploded, isometric, front view perspective of a thirdpreferred embodiment of a front-loading syringe interface and syringesystem in accordance with the present invention;

FIG. 125 is an exploded, isometric, rear view perspective of the syringeinterface and syringe system shown in FIG. 124;

FIG. 126 is an isometric, front view perspective of a syringeincorporating syringe encoding;

FIG. 127A is a top, cross-sectional view of another embodiment of aninjector of the present invention;

FIG. 127B is an enlarged, top cross-sectional view of a first syringeinterface and a first piston of the injector of FIG. 127A to which asyringe is attached;

FIG. 127C is an enlarged, top cross-sectional view of a second syringeinterface and a second piston of the injector of FIG. 127A to which asyringe adapter is attached;

FIG. 128A illustrates an embodiment of a control interface for a controlroom control unit and an embodiment of a control interface for a scanroom control unit for the injector of FIG. 127A;

FIG. 128B illustrates several modes of injection provided by the controlroom interface of FIG. 128A;

FIG. 128C illustrates a protocol for a six-step sequential injection;

FIG. 128D illustrates a protocol for simultaneous injection of 40 ml ofcontrast and 10 ml of saline into a single injection site;

FIG. 128E illustrates the state of a scan room control interface displayprior to initiation of auto loading for the protocol of FIG. 128D;

FIG. 128F illustrates the display of FIG. 128E after initiation of autoloading;

FIG. 128G illustrates the display of FIG. 128E after the syringes arefilled;

FIG. 128H illustrates the display of FIG. 128E after auto priming;

FIG. 128I illustrates the display of FIG. 128E half way through theinjection procedure;

FIG. 128J illustrates the display of FIG. 128E after the injectionprocedure has been completed;

FIG. 129A illustrates an embodiment of an injector system incorporatingthe scan room control interface of FIG. 128A; and

FIG. 129B illustrates the injector system of FIG. 129A including a fluidpath for simultaneous injection from multiple syringes into differentinjection sites on a patient;

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 discloses an injector apparatus 10 of the general type disclosedin U.S. Pat. No. 5,383,858 for injecting a liquid contrast media into avascular system of an animal. Injector apparatus 10 has a front-loadingconstruction. The apparatus of FIG. 1 utilizes a syringe 12 capable ofbeing front-loaded into a mounting assembly 14 associated with a frontwall 16 of a housing 18 of an injector 20 by a first releasablemechanism 22. Syringe 12 is capable of functioning in an injectionoperation without the use of a pressure jacket (although the syringe maybe used in an injector with a pressure jacket, as will be described ingreater detail in connection with FIGS. 4 and 5, below). To the extentnot inconsistent with this disclosure, the disclosure of the '858patent, which is assigned to Medrad, Inc., the Assignee of the subjectapplication, is incorporated herein by reference.

With reference to FIG. 1 and the first releasable mechanism 22, themounting assembly 14 is provided with an essentially cylindricalinterface 26 for receiving a rearward end of syringe 12. Interface 26includes an annular surface 28, which may be cylindrical or conicallytapered. As best shown in FIGS. 6 and 7, annular surface 28 includes adistal ledge 29, which is engaged by tabs 30 on the rearward end ofsyringe 12. Syringe 12 is inserted into cylindrical interface 26 untiltabs 30 engage ledge 29 to secure syringe 12 to the injector 20.

Among other things, tabs 30 distribute the attachment force of syringe12 to ledge 29 equally around the syringe. This helps to maintain aconnection between syringe 12 and ledge 29 even if syringe 12 deforms or“ovals” under pressure during use. This overcomes a potential shortfallwith conventional front-loading injector systems, which may not functionas well if the syringe ovals under pressure during use.

Referring again to FIG. 1, syringe 12 comprises an elongated maintubular body or barrel 32 and a coaxial discharge injection section 34,interconnected by an intermediate conical portion 36. A plunger 38 isslidably positioned within the tubular body 32 and is connectable to asecond releasable mechanism 40 on a piston 42 in the injector housing18. Second releasable mechanism 40 is formed in part by plunger 38 andin part by piston 42, as set forth in greater detail below.

Piston 42 and plunger 38 cooperate to eject fluid contained withinsyringe 12 in a desired quantity and at a desired rate. Secondreleasable mechanism 40 is designed to facilitate axial movement ofplunger 38 in either direction when actuated. Second releasablemechanism 40 is also designed to engage or disengage plunger 38 frompiston 42 no matter where plunger 38 sits in tubular body 32. Further inthis connection, the actuating mechanism, which reciprocates the plunger38 in the syringe tubular body 32, comprises piston 42 or a reciprocabledrive member. The drive member or piston 42, while reciprocable, doesnot need to be rotatable.

With reference to FIG. 1, to be mounted, syringe 32 is inserted intointerface 26 in mounting assembly 14. As best shown in FIGS. 6 and 7,tabs 30 initially move past annular surface 28 where they engage ledge29 to securely hold syringe 12 to mounting assembly 14. As best shown inFIGS. 2 and 7, mounting assembly 14 further includes a forwardlyprojecting annular ring or collar 44, which functions to assureperpendicular engagement between plunger 38 and piston 42. As explainedabove, forwardly projecting annular ring or collar 44 also functions asa seal between a flange 46 on syringe 32 and mounting assembly 14.

Resilient annular sealing flange 46 surrounds tubular body 32 of syringe12 and is disposed forward of tabs 30 a preselected distance essentiallyequal to a width of annular surface 28. Thus, when syringe 12 isinserted into interface 26 in mounting assembly 14 until sealing flange46 engages annular ring 44, annular ring 44 and flange 46 create a sealbetween syringe 12 and mounting assembly 14.

The foregoing mounting arrangement possesses a number of advantages. Theattachment of tabs 30 to the periphery of the rearward portion ofsyringe 12 minimizes wobble of syringe 12 during an injection operation.While minimizing wobble, tabs 30 also permit syringe 12 to rotate freelywithin interface 26. Tabs 30 also prevent syringe 12 from disengagingfrom injector 20. The seal between annular ring 44 and flange 46 alsoprevents contrast media spilled from discharge end 34 of syringe 12 fromflowing into injector housing 18 (as illustrated in FIG. 2) andeliminates the need for constructing the respective parts to excessivelytight tolerances. To enhance the sealing capability between flange 46and annular ring 44, a suitable O-ring (not shown) may be providedoptionally therebetween.

With further reference to FIG. 1, the apparatus also includes a systemfor transmitting syringe information from syringe 12 to an injectorcontroller 51. Syringe 12 is provided with an encoding device 48 forwardof tabs 30 but rearward of flange 46. Encoding device 48 may be a barcode or any other suitable encoding device known to those skilled in theart. When attaching syringe 12 to the mounting assembly 14, if syringe12 is rotated after tabs 30 engage ledge 29, a sensor 50 is provided inannular surface 28 to read the encoding device 48. Sensor 50 thenforwards the associated signals to injector controller 51, whichinterprets the signals and modifies the function of the injector 20accordingly. Examples of the information which could be encoded onencoding device 48 include dimensions of syringe 12, volume of syringe12, content of syringe 12 (in the case of a pre-filled syringe),manufacturing information such as lot numbers, dates and tool cavitynumber, recommended contrast media flow rates and pressures, andloading/injection sequences.

As an alternative to encoding device 48 being a bar code, encodingdevice 48 also could include machine-readable raised or recessedsurfaces. The raised or recessed surfaces could then be read by injectorsensor 50, mounted in annular surface 28, in a manner similar to thatfor reading a bar code. In addition to encoding device 48, one mightalso use a mechanically readable device (e.g. a slot, hole, orprojection on the syringe 12 or plunger 38) to register against a switchon the mounting assembly 14. Alternatively, an optically readable device(e.g. characters, dots and other geometric shapes) could be employed tosend information concerning the type of syringe used to the intelligentcircuits of injector 20.

In FIG. 1, since syringe 12 is being used in this embodiment without apressure jacket, for strength and visibility of the contents of syringe12, the syringe 12 may be formed of a clear PET polyester material. Inthe alternative, the wall of syringe 12 may be formed of polypropylenereinforced by providing a series of annular ribs on tubular body 32 ofsyringe 12 in longitudinally spaced relationship. (This arrangement isillustrated in FIG. 5 of the '858 patent.) As discussed in the '858patent, by suitably spacing the ribs along the length of tubular body32, such as in equal increments, the ribs also can perform the dualfunction of serving as volumetric gradations for the purpose ofindicating the amount of contrast media in syringe 12.

With reference to FIGS. 1 and 2, tubular body 32 of syringe 12 also maybe provided with an indicating mechanism 52 for readily detecting thepresence or absence of a liquid contrast media in syringe 12. In thisinstance, detecting mechanism 52 includes a plurality of integrallymolded, textured dots on syringe 12, which provide a visual indicationof whether the syringe contains liquid or air. More specifically, whenviewed against an air background, dots 52 appear oval-shaped, but whenviewed against a liquid contrast media background, which has a differentindex of refraction than air, dots 52 appear circular. The details ofindicating mechanism 52 are described in detail in U.S. Pat. No.4,452,251, assigned to Medrad, Inc., the Assignee of the subjectapplication. To the extent not inconsistent with the present disclosure,the contents of U.S. Pat. No. 4,452,251 are incorporated herein byreference.

FIG. 3 illustrates the internal construction of the syringe dischargeend 34. Specifically, while a rearward portion 54 of discharge end 34 isof tapered conical construction, a forward connector portion 56 is ofgenerally cylindrical construction and formed with internal screwthreads 58 for attaching a connecting tube to discharge end 34. Further,an injection nozzle 60 of reduced diameter is disposed within thescrew-threaded cylindrical connector portion 56 and is integrally moldedwith tapered rearward portion 54 of discharge end 34 adjacent the pointat which the tapered and cylindrical portions merge together.

FIGS. 4 and 5 illustrate an alternate embodiment of the presentinvention in which a front-loading syringe 112 is mounted on the frontof a pressure jacket 170, preferably formed of a strong clear plastic,such as polycarbonate. Pressure jacket 170 is in the form of anelongated tubular member that is suitably mounted at its rearward end ina mounting assembly 124 on housing front wall 116, by fitting the flangeof pressure jacket 170 into the collar on the mounting assembly 124.Pressure jacket 170 also has a forward open end 172 for receiving thesyringe 112.

In this embodiment, an annular surface 174 with a distal ledge 175 isprovided adjacent to the forward open end 172 of the pressure jacket170. Annular surface 174 is similar in construction to annular surface28 in the embodiment illustrated in FIGS. 1 and 7. Similarly, a tubularbody 132 of syringe 112 includes tabs 180 at a position adjacent itsforward end for engagement with ledge 175 when tubular body 132 has beeninserted into pressure jacket 170.

In addition, at the forward end of syringe 112, on opposite sides of adischarge end 134, a pair of reinforcing, loop-shaped handles 162, forfacilitating handling of the syringe 112, is integrally molded withdischarge end 134 and a tapered conical intermediate portion 136. Inother respects, while not specifically disclosed and described, it is tobe understood that various other features of the embodiment of theinvention disclosed in FIGS. 1-3, 6 and 7 may be incorporated into theembodiment of FIGS. 4 and 5, as desired.

In use, the syringe 112 of FIGS. 4 and 5 may be mounted in pressurejacket 170 with piston 142 of injector 120 either in a retractedposition, as shown in FIG. 4, or in an advanced position, as shown inFIG. 5. For example, with piston 142 in the retracted position, as shownin FIG. 4, plunger 138 is disposed at the rearward end of syringe 112.Syringe 112 then is inserted into the open end 172 of the forward end ofpressure jacket 170 until second releasable mechanism 140 engages withplunger 138.

In FIG. 5, in which piston 142 is in a forward position, the mounting ofsyringe 112 into pressure jacket 170 is the same as shown in FIG. 4,except that plunger 138 also is in its forward position in syringe 112.In other respects, the mounting of syringe 112 on pressure jacket 170 isessentially the same as previously described with respect to FIG. 4.However, having syringe plunger 138 and piston 142 in their forwardpositions, as shown in FIG. 5, has several advantages over the rearwardposition arrangement of FIG. 4. For example, because syringe plunger 138and piston 142 are already in their forward positions, it is notnecessary to move them forward to expel air from the syringe 112 inpreparation for a syringe-filling operation. Rather, plunger 138 andpiston 142 can immediately be retracted to aspirate fluid into thesyringe 112. Similarly, after an injection operation has been completed,additional time is saved by not having to retract plunger 138 and piston142 in preparation for a next injection operation.

In summary, a new and improved system by which an injection syringe,such as syringe 12 in the embodiment of FIGS. 1-3, can be readilymounted upon and/or removed from injector housing 18, has beendisclosed. For this purpose, the first releasable mechanism 22, by whichsyringe 12 is attached to or removed from injector housing 18, andsecond releasable mechanism 40, by which plunger 38 of syringe 12 isdrivingly connected to or released from piston 42 of injector 20cooperate to produce their respective connections and disconnectionssimultaneously and/or independently. Another advantage is that plunger38 is capable of being placed in a driven or undriven state at any pointalong its path, whereby syringe 12 may be disengaged from injector 20without having to retract piston 42, or having to first disconnectsyringe 12 from a patient being injected before retracting piston 42.

Other desirable features of the invention include the construction offirst releasable mechanism 22, in which syringe 12 is mounted uponinjector housing 18 with a secure fit, which is advantageous from thestandpoint of minimizing syringe wobble and disengagement during aninjection operation, and eliminating the need for excessively tightmanufacturing tolerances. Encoding device 48 on syringe 12, incooperation with sensor 50 on injector 20, also is advantageous from thestandpoint of providing “custom programming” of injector 20. Eliminationof a pressure jacket also is desirable from the standpoint of bettervisibility of the contents of syringe 12, better heat transfer to thesyringe contents and decreased cleaning and maintenance otherwise neededdue to, e.g., scratching or contamination with contrast media of thepressure jacket.

In order to eliminate the need for a pressure jacket, syringe 12 alsomay be made of a relatively strong clear plastic, or may be providedwith annular reinforcing ribs (not shown), which may be spaced tofunction as volumetric gradations. Further, detection of the presence ofair in syringe 12 is facilitated by the indicating mechanism 52 in FIGS.1 and 2, in the form of dots 52 molded into syringe tubular body 32.Dots 52 appear visually as either oval-shaped or circular, dependingupon whether the tubular body contains air or liquid, respectively. Inaddition to functioning as a part of first releasable mechanism 22 forsyringe 12, syringe resilient annular flange 46 also cooperates withannular ring 44 to create a seal to prevent contrast media spilled fromthe injection end of syringe 12, from flowing into injector 20, as shownin FIG. 2. The embodiment of the invention shown in FIGS. 4 and 5provides a system by which various other advantages, including timesavings in syringe-filling and syringe-changing operations, can beachieved utilizing a pressure jacket, such as pressure jacket 170mounted on injector housing front wall 116.

FIG. 6 illustrates a cross-section of syringe 12 after it has beeninserted into injector 20 so that tabs 30 engage ledge 29. Tabs 30 arepreferably substantially V-shaped members that preferably form a ringencircling the rearward end of tubular body 32. Alternately, one or moretabs may be separately disposed around the rearward end of the body 32.Each of tabs 30 on the ring has a first end 62 and a second end 64. (Anenlarged, perspective illustration of the ring of tabs 30 is shown inFIG. 8.) As shown in FIG. 8, first ends 62 of tabs 30 engage ledge 29when syringe 12 is inserted into interface 26 of injector 20. First ends62 of tabs 30 are separated from one another by gaps 66 around theperiphery of tubular body 32 so that they are flexible and can easilycompress. Second ends 64 of tabs 30, on the other hand, form a ring thatattaches to tubular body 32.

Syringe 12, therefore, is easily connected to the injector 20 simply byinserting the rearward end of tubular body 32 into cylindrical interface26. During insertion of tubular body 32 into cylindrical interface 26,annular surface 28 compress first ends 62 of tabs 30 until first tabs 62clear ledge 29. Once first ends 62 clear ledge 29, they spring open andengage ledge 29 to prevent the removal of tubular body 32 from interface26.

Removal of syringe 12 from housing 20 is enabled by a reciprocatingcollar 68 that is disposed within injector 20 at a location behindsyringe 12 (once inserted into cylindrical interface 26). Reciprocatingcollar 68 is preferably a cylindrical member that can move in bothforward and rearward directions, as illustrated by the arrow in FIG. 7.During an injection operation, reciprocating collar 68 is in its restposition behind tabs 30 so that first ends 62 remain engaged with ledge29. Upon completion of the injection operation, in order to removesyringe 12 from interface 26, reciprocating collar 68 is pushed forwardtoward ledge 29 by an actuating mechanism (not shown) or manually sothat it compresses first ends 62 so that they can easily slide out frombehind ledge 29. Syringe 12 then can be easily removed from injector 20.

Alternatively, tabs 30 may be caused to disengage from ledge 29 byretracting annular surface 28 in the direction of arrow 1100 in FIG. 33.To do this, annular surface 28 is made of a number of segments 1102, allof which can retract to release syringe 32. In still another alternativeembodiment as illustrated in FIG. 34, a portion of the inner surface1104 may be moved inwardly in the direction indicated by arrow 1106 tocollapse tabs 30 so that syringe 32 may be disengaged from ledge 29.Other embodiments of these two arrangements will be readily understoodby those skilled in the art.

In the case where syringe 112 is to be inserted into a pressure jacket170 (as illustrated in FIGS. 4 and 5), tabs 180 serve the same functionas tabs 30, except of course that they are located toward the forwardend of syringe 112. In fact, but for the location of tabs 180 on tubularbody 132, it is contemplated for the present invention that tabs 180have the same construction as tabs 30. When tabs 180 are insertedthrough open end 172 of pressure jacket 170, annular surface 174compresses first ends 62 of tabs 180 until they clear ledge 175. Syringe112 is then securely held in place. When it becomes necessary to removesyringe 112 from pressure jacket 170, a reciprocating collar 68 extendsforward within the pressure jacket 170 (as described in more detailbelow) to compress first ends 62 so that they no longer engage ledge174. Syringe 112 can then be removed from pressure jacket 170.

It is not necessary for tabs 30, 180 to have a V-shaped appearance asillustrated in FIGS. 1 and 4-8, however. It is contemplated for thesecond embodiment of tabs 30 that they have a b-shaped appearance, asillustrated in FIG. 9. When tabs 30 have a b-shaped appearance, they maybe formed integrally with the end of syringe 412. Tabs 30, when theyhave a b-shaped appearance, have bulbous first ends 70 that extendoutwardly from second ends 72, which are separated from adjacent tabs 30by gaps 71 (as best shown in FIGS. 14 and 15). As with first ends 62,first ends 70 engage ledge 29 when syringe has been inserted intoinjector housing 18. As with first ends 62, reciprocating collar 68 actsupon first ends 70 to disengage them from ledge 29 when syringe 412 isto be removed from injector 20.

For each of the embodiments of tabs 30 contemplated by the presentinvention, it is also contemplated that the number of tabs used may bevaried while remaining within the scope of the present invention. Forexample, for syringe 212, illustrated in FIGS. 10 and 11, it iscontemplated that only one tab is provided at the end of the syringe. InFIGS. 10 and 11, only one tab 30 with first end 70 and second end 72 isillustrated. It should be understood, however, that tab 30 with firstend 62 and second end 64 could be easily substituted therefor.

While a single tab 30 may be used, preferably the syringe has at leasttwo tabs, because the tabs should flex in order to function optimally.Such a syringe 312, with at least two tabs, is illustrated in FIGS. 12and 13. When two tabs are included on syringe 312, it is contemplatedthat they be disposed on opposite sides of tubular body 32 to addstability to the secure engagement of syringe 312 to injector 20. Thetabs may be appropriately sized and optionally may be of differentcircumferential dimension.

In an alternate embodiment of the pressure-jacketed injector systemshown in FIG. 32, it is contemplated that a syringe cap 1000 could beprovided at the end of the pressure jacket 1002 to hold a syringe 1032therein. Alternately, cap 1000 could be attached to or molded as a partof syringe 1032 and need not be a separate element. As shown in FIG. 32,pressure jacket 1002 is a modified version of pressure jacket 170illustrated in FIGS. 4 and 5. According to the teachings of the presentinvention, cap 1000 includes tabs 1004 about its periphery. Tabs 1004engage a ridge 1006 that encircles the end of pressure jacket 1002. Todisengage tabs 1004 from ridge 1006, a reciprocating ring 1008 slidesalong the exterior of pressure jacket 1002. Ring 1008 includes a taperedsurface 1010 to facilitate removal of tabs 1004 from ridge 1006. Theactuator of ring 1008 is not shown. However, those skilled in the artwill readily recognize that ring 1008 may be operated either manually,mechanically, or electrically (or in any other fashion suitable todisengage tabs 1004 from ridge 1006).

In another alternate embodiment of the apparatus described in relationto FIG. 32, the tabs could extend from the cap (which could be separatefrom, attached to, or molded with the syringe) to engage annular member174 at the end of pressure jacket 170 in the same way that tabs 180engage annular member 174 in the embodiment illustrated in FIGS. 4 and5. As with the embodiment illustrated and described in relation to FIGS.4 and 5, a reciprocating collar should then be positioned withinpressure jacket 170 to disengage the tabs from the annular member.

The elements for the releasing mechanism are illustrated in FIGS. 38 and39. There, reciprocating collar 1402 is shown internal to pressurejacket 170. As illustrated, reciprocating collar 1402 is disposed at theend of at least two supports 1404 that are also within the interior ofpressure jacket 170. To accommodate supports 1404, interior wall 1406 ofpressure jacket 170 includes at least two tracks 1408 in which supports1404 slide. When syringe 1032 is to be removed from pressure jacket 170,reciprocating collar 1402 is moved forward within pressure jacket 170 todisengage the tabs on syringe 1032 from engagement with annular member174.

This arrangement also may be used in connection with the pressure jacketsystem illustrated and described in connection with FIGS. 4 and 5. Whensyringe 132 is to be removed from pressure jacket 170, reciprocatingcollar 1402 is moved forward within pressure jacket 170 to compress tabs180 so that they no longer engage annular member 174. Once tabs 180 areclear of annular member 174, syringe 132 may be removed from pressurejacket 170.

In the case where syringe 112 is to be inserted into pressure jacket 170as shown in FIGS. 4 and 5, b-shaped tabs 190 may be added to the forwardend of syringe 112 in the same manner that tabs 180 were applied. Asshown in FIG. 16, tabs 190 essentially comprise a ring 74 from whichsecond ends 72 of tabs 190 extend in a rearward direction. Ring 74 withtabs 190 form a V-shaped structure in cross-section, as illustrated inFIG. 17. As with tabs 180, when tabs 190 are inserted into pressurejacket 170 (as illustrated in FIGS. 4 and 5), they are compressed untilthey clear annular surface 174, whereupon they expand to engage ledge175. Tabs 190 hold syringe 112 securely in pressure jacket 170 untildisengaged by reciprocating collar 68.

The installation and removal of syringe 412 is illustrated in FIGS.18-20. In FIG. 18, syringe 412 is shown prior to insertion into injectorfront wall 16. Reciprocating collar 68 is shown in a rest state behindwhere first ends 70 of tabs 30 will rest after they clear annularsurface 128 and rest against distal ledge 129. In this embodiment,annular surface 128 is illustrated with a tapered cross-section ratherthan the cylindrical cross-section shown in FIGS. 7 and 9. A taperedcross-section may facilitate insertion of syringe 412 into interface 26because the taper may help to squeeze first ends 70 of tabs 30 duringinsertion of syringe 412 into injector 20. In addition, annular surface128, when tapered, acts as a guiding surface for syringe 412 (or anyother embodiment disclosed) so that syringe 412 may be inserted intofront wall 16 at even greater angular approaches. In other words,syringe 412 may be inserted easily into front wall 16 even when syringe412 is not oriented exactly with the central axis of interface 26.

Once syringe 412 has been fully inserted into front wall 16, tabs 30expand to engage ledge 129, as illustrated in FIG. 19. Syringe 412 isthen securely held in place. As shown in FIG. 19, reciprocating collar68 remains in its rest position until after the injection operation iscompleted.

After the injection operation is completed, reciprocating collar 68 ismoved forward to compress first ends 70 of tabs 30 to disengage tabs 30from ledge 129. FIG. 20 shows reciprocating collar 68 in this forwardposition. The compression of tabs 30 is also illustrated. The syringe412 may then be removed from injector 20.

The present invention also contemplates that it may be desirable toconnect a syringe to an adapter 500 before connecting the syringe toinjector 20. The adapters could be disposable or reuseable, as would beunderstood by those skilled in the art. The syringe may be of differentconstruction from that disclosed herein, as would be understood by thoseskilled in the art. An adapter for a syringe is described in U.S. Pat.No. 5,535,746, issued to Hoover et al. on Jul. 16, 1996, the disclosureof which is incorporated herein by reference. Other patents that areexemplary of adapters include U.S. Pat. No. 5,520,653 and WO 97/36635,both of which are assigned to the Assignee of the present applicationand are incorporated herein by reference.

In the embodiment illustrated in FIG. 21, a syringe 412 with tabs 30having a b-shaped appearance snap-fits into a forward end 502 of adapter500. Of course, tabs with the V-shaped cross-section may be substitutedtherefor. Adapter 500 includes an annular surface 528 with a distalledge 529 within its forward end 502 to which first ends 70 of tabs 30engage to hold syringe 412 securely in place. Flange 46 of syringe 412may or may not be included to engage with forward end 502 of adapter 500to prevent contrast medium, should it leak, from entering injectorhousing 18 through adapter 500. The rearward end 504 of adapter 500 alsopreferably includes a flange 546 that mates with annular ring 44 onmounting assembly 14 of injector 20. Flange 546 serves the same functionas flange 46 on syringe 12, namely to prevent contrast medium (orwhatever fluid is included in syringe) from entering the injector 20.

If adapter 500 is attached to syringe 32, piston 42 may need to beadapted to accommodate the increased length of the overall construction.If so, a piston extender or adapter (not shown) may be attached to theend of piston 42, as would be understood by those skilled in the art.Alternatively, piston 42 could be constructed so that it is long enoughto accommodate syringes 32 of varying lengths.

In this particular embodiment, adapter 500 includes conventionalconnector elements 506, such as those described in U.S. Pat. No.5,535,746 or U.S. Pat. No. 5,383,858. So designed, adapter 500 permitssyringe 412 to be connected to an injector that is designed to acceptonly syringes with conventional connector elements 506.

As shown in FIG. 22, in an alternate embodiment of the adapter, it maybe necessary to adapt a conventional syringe for use in an injectordesigned to accept the syringes of the present invention. Here, adapter600 includes tabs 630 at its rearward end 604. Tabs 630 act and functionlike tabs 30 to secure adapter to housing 18 by engaging ledge 29 onmounting assembly 14. Tabs 630 are disengaged from ledge 29 byreciprocating collar 68. Adapter 600 may also include a flange 646 as inthe other embodiments that have been described above. While adapter 600is shown with a syringe having a ridged end inserted therein, it shouldbe understood that adapter 600 could be easily designed so that itsforward end 602 can accept conventional connector elements, such asthose described in U.S. Pat. No. 5,535,746 or U.S. Pat. No. 5,383,858.

FIGS. 23 and 24 illustrate two perspective views of the combination ofthe syringe 412 and adapter 600. In this embodiment, flange 46 has beenomitted. However, as illustrated in FIG. 22, flange 46 may be included.Naturally, as with syringe 212 (shown in FIGS. 10 and 11) and withsyringe 312 (shown in FIGS. 12 and 13), the adapter may include only onetab, two tabs, or more than two tabs 630. FIGS. 23 and 24 illustrateadapter 600 with a plurality of tabs.

Two embodiments of second releasable mechanism 40 for engaging andreleasing the syringe plunger and the injector piston will now bedescribed with respect to FIGS. 25-29. FIG. 25 illustrates anelectromagnetic release mechanism. FIGS. 26-29 illustrate anelectromechanical release mechanism.

As shown in FIG. 25, plunger 738 may be releasably connected to piston742 through an electromagnetic device. A forward end 702 of piston 742is provided with an electromagnetic coil 704 that can be activated byapplying a current through leads 706 that extend through piston 742. Atits rearward end 707, plunger 738 includes a magnetically attractivering 708, made of iron, for example, which is attracted toelectromagnetic coil 704 when electromagnetic coil 704 is activated. Thecross-sections of forward end 702 of piston 742 and of recess 710 inrearward end 707 of plunger 738 are cylindrical. This permits theengagement of piston 742 with plunger 738 regardless of the orientationof plunger 738 in the syringe.

Second releasable mechanism 40, as illustrated in FIG. 25, operates asfollows. When a syringe has been inserted into the interface on theinjector housing 18, piston 742 is extended into the syringe until itsforward end 702 mates with recess 710 of plunger 738. Electromagneticcoil 704 may then be activated to retract plunger 738. The attractionbetween magnetically attractive ring 708 and electromagnetic coil 704holds plunger 738 to the end of piston 742 during rearward movement ofpiston 742. Alternatively, electromagnetic coil 704 may be activatedbefore piston 742 is extended into the syringe to mate with plunger 738.Once plunger 738 and piston 742 are electro-magnetically attracted toone another, piston 742 may be moved as required within the syringe. Todisengage piston 742 from plunger 738, or to retract piston 742 withoutretracting plunger 738, one need only disengage the power supplied toelectromagnetic coil 704. Of course, the piston 742 may advance theplunger 738, for example, during an injection, without activatingelectromagnetic coil 704.

The second embodiment contemplated for second releasable mechanism 40involves an electromechanical connection between the piston and theplunger. This embodiment is illustrated in FIGS. 26-29.

In FIGS. 26-29, piston 842 has a forward end 802 that engages with arecessed area 804 formed in a rearward end 806 of plunger 838. Forwardend 802 of piston 842 includes protrusions 808 that retractably extendtherefrom. Protrusions 808 engage an indentation or channel 810 formedin the plunger 838, as illustrated in FIG. 27. A member 812 is enclosedby piston 842 and forward end 802. Member 812 is actuated by mechanism814, also contained within piston 842. Mechanism 814 receives powerthrough leads 816.

As shown in FIGS. 28 and 29, protrusions 808 are essentiallyrectangular. They are connected to one another through resilient members818. Resilient members 818 bias protrusions 808 so that they do notprotrude from forward end 802 of piston 842, as shown in FIG. 29.

The operation of second releasable mechanism 40 will now be described inconnection with FIGS. 26-29. When a syringe has been inserted into frontwall 16 of injector 20, piston 842 is extended forward to meet withplunger 838. When piston 842 extends forward, mechanism 814 isdeactivated so that member 812 is in a retracted condition, as shown inFIG. 29. In other words, member 812 is retracted so that it does not sitbetween protrusions 808. As a result, resilient members 818 biasprotrusions 808 so that they do not extend outside of forward end 802 ofpiston 842, as shown in FIG. 29.

Once forward end 802 of piston 842 mates with recessed area 804 inplunger 838, mechanism 814 is activated so that member 812 extendsforward to sit between protrusions 808, thereby forcing protrusions 808to extend outside of forward end 802 of piston 842. Protrusions 808,once extended, extend into channel 810 within plunger 838. Once soarranged, piston 842 is connected to plunger 838 so that rearwardmovement of piston 842 translates directly into a corresponding rearwardmovement of plunger 838.

When it becomes necessary to disengage the syringe from the injector, orto retract piston 842 without retracting plunger 838, mechanism 814 isactivated to withdraw member 812 from between protrusions 808. Oncewithdrawn, resilient members 818 bias protrusions 808 so that they nolonger engage channel 810. Piston 842 may then be withdrawn from plunger838.

Two additional second releasable mechanisms 40 will now be describedwith reference to FIGS. 35-37.

In the embodiment illustrated in FIG. 35, plunger 1238 may be releasablyconnected to piston 1242 through expansion of an elastomeric member 1202disposed at a forward end thereof. Elastomeric member 1202 is acylindrical element with external walls 1204 and internal walls 1206. Arod 1208 extends through piston 1242 and connects to an actuator 1210 ata forward end of rod 1208 closest to plunger 1238. Actuator 1210 has afrustoconical shape on a side facing elastomeric member 1202. Thefrustoconical shape defines an inclined surface 1212 on actuator 1210.The diameter of elastomeric member 1202 is slightly smaller than thediameter of the hole 1214 in plunger 1238. Also, the diameter ofactuator 1210 is smaller than the diameter of hole 1214.

The operation of the second releasable mechanism 40 illustrated in FIG.35 will now be described. Because the diameter of hole 1214 in plunger1238 is larger than the diameter of elastomeric member 1202 and ofactuator 1210, when piston 1242 is pushed forward, elastomeric member1202 and actuator 1210 easily fit into hole 1214. Plunger 1238 can thenbe advanced by piston 1242 without a connective engagement existingtherebetween. However, once positioned in this manner, to connectivelyengage the plunger 1238 (e.g., to retract plunger) actuator 1210 ispulled toward elastomeric member 1202 by rod 1208, as shown by arrow1216 in FIG. 35. The pressure from actuator 1210 compresses elastomericmember 1202 so that external sides 1204 swell or expand from theirunstressed condition. The approximate shape of the swelled walls 1218 ofelastomeric member 1202 is shown in dotted line format in FIG. 35.Swelled walls 1218 engage walls 1220 of hole 1214 so that piston 1242releasably engages plunger 1238. Plunger 1238 can now be retracted to,for example, aspirate fluid into the syringe.

The embodiment of second releasable mechanism 40 shown in FIGS. 36-37will now be described. As shown in FIGS. 36-37, plunger 1338 engagespiston 1342 through segmented member 1302. Segmented member 1302 is madeof a number of separate elements 1304 as shown in the end viewillustration of FIG. 37. Separate elements 1304 may be made from anysuitable material, such as an elastomeric material, so long as thematerial preferably (1) can substantially withstand repeated deformationand (2) returns substantially to its original condition when no longersubject to a deforming stress. Segmented member 1302 is disposed at aforward end of piston 1342. A rod 1306 extends through the middle ofpiston 1342 and extends at least partially into a central bore 1308 ofsegmented member 1302.

To releasably connect plunger 1338 with piston 1342, piston 1342 ismoved forward until segmented member 1302 is disposed within a hole 1310formed in plunger 1338. Rod 1306 is then moved forward, in the directionshown by arrow 1312, until rod 1306 is at least partially disposedwithin segmented member 1302. Since the diameter of rod 1306 is greaterthan the diameter of bore 1308, the insertion of rod 1306 into bore 1308pushes segmented members 1304 outwardly until they reach a deformedposition 1314 shown in dotted lines in both FIG. 36 and FIG. 37. Whendeformed, segmented members 1304 engage walls 1316 of hole 1310 inplunger 1338 to create a releasable engagement between plunger 1338 andpiston 1342.

For each of the second releasable mechanisms described in FIGS. 25-29and 35-37, the advantage that the mechanisms provide is that the pistonneed not be oriented in any specific manner with the plunger in order tofacilitate a connection between the piston and plunger. Regardless ofthe orientation of the piston and the plunger, the two can easily matewith one another and can be easily disengaged from one another.

In addition, if for example a prefilled syringe is mounted on theinjector, it may not be necessary to retract the plunger within thesyringe to draw fluid within the syringe for subsequent injection. Insuch a case, the piston may be operated in a “push-only” mode that doesnot require engagement between the piston and the plunger. If operatedin this manner, the engagement mechanism need not be activated at all.Alternatively, if the injector is designed to handle only prefilledsyringes, no readily releasable mechanism need be provided.

The plunger of the present invention may also include a pressure sensorlike the sensors described in U.S. Pat. No. 5,808,203, issued to Nolan,Jr. et al. on Sep. 15, 1998, and assigned to the Assignee of the presentapplication. The disclosure of U.S. Pat. No. 5,808,203 is incorporatedherein by reference, to the extent that it is not inconsistent with theinstant disclosure.

FIGS. 30 and 31 illustrate the sensor that can be included in theplunger of the present invention. Plunger 938 preferably comprises abase 902 with a passage 904 therethrough. A sensing member 906 isdisposed within passage 904 to be in operative contact with a portion Pof contact surface 908. Sensing member 906 is preferably biased forward,for example, via a spring 910. As fluid pressure within the syringe (notshown) increases, portion P of contact surface 908 is deformed as shownin FIG. 31. This deformation of portion P causes sensing member 906 tomove rearward through passages 904 and 912 and 914 in piston 942. Themovement of sensing member 906 is monitored with a sensor 916 preferablydisposed within piston 942. Because the degree of movement of sensingmember 906 is a function of the pressure of the fluid medium within thesyringe, the pressure of the fluid medium can be determined therefrom.Sensor 916 is preferably connected to a data collection and/or controldevice via leads 918.

While FIGS. 30 and 31 describe one possible embodiment of a sensor thatcan be incorporated into the plunger of the present invention, it shouldbe noted that any other suitable sensor might be included. In addition,the sensor need not detect only the pressure of the fluid. As would beunderstood by those skilled in the art, the sensor may measure a numberof different parameters including amount, pressure and density of thefluid in the syringe.

Also, the plunger may contain encoding elements that are read or sensedby the injector or injector piston to identify the syringe and/or itscontents. In this embodiment, the encoding elements, such as anintegrated circuit, are included on the plunger rather than the syringe.The encoded elements then may be read electronically when the plungercontacts the piston. The plunger may contain information such as thecontents and volume of the syringe as well as other information neededfor the procedure or for billing purposes. One example of such a systemis described in PCT Publication No. WO 99/65548, which is incorporatedherein by reference.

The present invention is often shown and described herein in terms ofcooperating syringe interfaces and syringes. The terms “syringeinterface” and “syringe interfaces” as used herein can be incorporatedin or integrated with new medical injectors or configured as syringeadapters mountable on or associated with existing or conventionalmedical injectors, such as the injector shown and described in U.S. Pat.No. 5,383,858, the contents of which are hereby incorporated byreference, to allow the installation of the syringes of the presentinvention thereon.

FIGS. 40A-40C illustrate another embodiment of a front-loading syringeinterface and syringe system 1500 in accordance with the presentinvention. The system 1500 includes a syringe 1512 and a syringeinterface 1514. The syringe 1512 includes a body or barrel portion 1516having a rear end 1520 and a front end 1517 defining a fluid dischargeend 1518. Preferably, at least one tab or mounting member 1522 isassociated with the barrel portion 1516 adjacent to or at the rear end1520 of the syringe 1512. In addition, a flange 1524 is preferablypositioned forward of the mounting member 1522 to facilitate theengagement of the syringe 1512 to the syringe interface 1514 and/or toprevent fluid expelled from the discharge end 1518 of the syringe fromentering into the syringe interface 1514 and the injector (not shown),as described in more detail in U.S. Pat. No. 5,383,858.

Preferably, the mounting member 1522 is disposed around thecircumference of the barrel portion 1516 and includes an inclinedsurface 1526 that defines a shoulder 1528. The function of the mountingmember 1522 will be described in more detail below. Alternately, themounting member 1522 may extend around only a portion of thecircumference of the barrel portion 1516 or may be formed in discretesegments.

(Unless otherwise noted, the syringe 1512 (and its components parts)described above applies to the remaining embodiments of the presentinvention discussed and described below with respect to FIGS. 40A-47F.)

As best shown in FIGS. 40A and 40C, the syringe interface 1514 is in an“open” position ready to accept the syringe 1512. The syringe interface1514 includes a base member 1530 and two cooperating syringe-retainingmembers 1532. However, in alternate embodiments, three or more retainingmembers 1532 could be provided. Preferably, each of the retainingmembers 1532 is associated with the base member 1530 by means of twoangled rail members 1534. However, in alternate embodiments, one, threeor more members 1534 may be used to associate each retaining member 1532with the base member 1530.

Further, each retaining member 1532 preferably defines a contact surface1533 and a channel 1536 to capture and retain the mounting member 1522on the syringe 1512. In addition, the retaining members 1532 arepreferably associated with one another by means of two rail members1538. Once again, in alternate embodiments, one, three or more railmembers 1538 may be used to associate the retaining members 1532 withone another.

To install the syringe 1512 on the syringe interface 1514, the syringe1512 is moved axially (in the direction of Arrow A in FIG. 40A) into thespace defined between the retaining members 1532. When the flange 1524on the syringe 1512 engages the contact surfaces 1533 on the retainingmembers 1532, the retaining members 1532 are urged toward the basemember 1530 along the rail members 1534. Because the rail members 1534are angled in toward the center of the base member 1530, the railmembers 1534 operate to cause the retaining members 1532 to move towardeach other along the rail members 1538 and to “collapse” around the rearend 1520 of the syringe 1512. As the retaining members 1532 collapse onthe syringe 1512, the retaining members 1532 cooperate to capture themounting member 1522 within the channels 1536 to securely engage thesyringe 1512 with the syringe interface 1514.

Any suitable type of locking mechanism (not shown), as is known in theart, may be used to secure the retaining members 1532 together to retainthe syringe 1512 within the syringe interface 1514. To remove thesyringe 1512 from the syringe interface 1514, the lock must first beunlocked and the retaining members 1532 moved apart (e.g., by hand or bymeans of a lever or any other suitable art-recognized manipulativedevice) to free the mounting member 1522 from the channels 1536.

Another embodiment of the syringe interface and syringe system 1600 isshown in FIGS. 41A-41D. The system 1600 includes a syringe 1512 and asyringe interface 1614. As best shown in FIGS. 41B and 41C, the syringeinterface 1614 is in an “open” position ready to accept the syringe1512. The syringe interface 1614 includes a base member 1630 and twocooperating syringe-retaining members 1632. The retaining members 1632are preferably connected together and associated with the base member1630 by means of a pivot pin 1631 or other suitable mechanism (see FIG.41D). In addition, the retaining members 1632 are associated with thebase member 1630 by means of pins 1629 (see FIG. 41D) that areassociated with the retaining members 1632 and captured within slots1635 defined in the base member 1630.

Further, each retaining member 1632 preferably defines a channel 1636 tocapture and retain the mounting member 1522 on the syringe 1512. As bestshown in FIGS. 41B and 41C, a spring pin 1637 (or other suitable lockingmechanism) is connected to one retaining member 1632 and a channel witha pin recess 1640 is defined in the other retaining member 1632. Inaddition, two barrel guide rails 1639 are preferably defined in the basemember 1630.

To install the syringe 1512 on the syringe interface 1614, the syringe1512 is moved downwardly (in the direction of Arrow B in FIG. 41B) intothe space defined between the retaining members 1632. The barrel 1516 ofthe syringe 1512 is guided into position between the retaining members1632 by the barrel guide rails 1639 in the base member 1630. When thesyringe barrel 1516 engages the pivot ends 1651 of the retaining members1632 (see FIG. 41C), the retaining members 1632 are urged to collapsearound the rear end 1520 of the syringe 1512. The pins 1629, riding inslots 1635 defined in the base member 1630, direct and control thearcuate motion of the retaining members 1632 into engagement around thesyringe 1512. As the retaining members 1632 collapse on the syringe1512, the retaining members 1632 cooperate to capture the mountingmember 1522 within the channels 1636 to securely engage the syringe 1512with the syringe interface 1614.

Further, when the retaining members 1632 collapse around the syringe1512, the spring pin 1637 runs along the channel and locks into the pinrecess 1640 to secure the syringe 1512 within the syringe interface1614. To remove the syringe 1512 from the syringe interface 1614, thespring pin 1637 must be removed from the pin recess 1640 to unlock theretaining members 1632 and the retaining members 1632 moved (e.g., byhand or by any suitable lever means) from engagement with the syringe1512. At this point, the syringe 1512 can be removed by either movingthe syringe 1512 upwardly (in the opposite direction of Arrow B) oraxially (in the direction of Arrow C in FIG. 41B).

FIGS. 42A-42D illustrate an alternate embodiment 1700 of the syringeinterface and syringe system 1600 shown in FIGS. 41A-41D. The system1700 includes a syringe 1512 and a syringe interface 1714. The syringeinterface 1714, as best shown in FIGS. 42C and 42D, differs from thesyringe interface 1614 in FIGS. 41A-41D in that the retaining members1732 include pivot ends 1751 located at the ends of the retainingmembers 1732 remote from the pivot pin 1731. Further, the retainingmembers 1732 are preferably spring-biased in the “closed” or “engaged”position, as best shown in FIG. 42D, to retain the syringe 1512 withinthe syringe interface 1714.

To install the syringe 1512 on the syringe interface 1714, the syringe1512 is moved downwardly (in the direction of Arrow D in FIG. 42B) intoengagement with the retaining members 1732. When the syringe barrel 1516engages the pivot ends 1751 of the retaining members 1732, the retainingmembers 1732 are urged apart against the spring force to allow thesyringe barrel 1516 to pass between the pivot ends 1751 and into thespace defined between the retaining members 1732. The syringe mountingmember 1522 is guided by the channels 1736 defined in the retainingmembers 1732 to correctly position the syringe 1512 within the syringeinterface 1714. Once the syringe 1512 passes the pivot ends 1751, theretaining members 1732 are urged by the spring force to collapse aroundthe rear end 1520 of the syringe 1512. The pins 1729, riding in slots1735 defined in the base member 1730, direct and control the arcuatemotion of the retaining members 1732 into engagement around the syringe1512. As the retaining members 1732 collapse on the syringe 1512, theretaining members 1732 cooperate to capture the mounting member 1522within the channels 1736 to securely engage the syringe 1512 within thesyringe interface 1714.

To remove the syringe 1512 from the syringe interface 1714, the syringe1512 is moved upwardly (in the opposite direction of Arrow D) againstthe pivot ends 1751 of the retaining members 1732. When the upward forceon the syringe 1512 overcomes the spring force holding the retainingmembers 1732 together, the retaining members 1732 will move apart andallow the syringe 1512 to slide free from the syringe interface 1714.

FIGS. 43A-43I illustrate another alternate embodiment 1800 of thesyringe interface and syringe systems 1600, 1700 shown in FIGS. 41A-42D.The system 1800 includes a syringe 1512 and a syringe interface 1814.The syringe interface 1814, as best shown in FIGS. 43B and 43H, differsfrom the syringe interfaces 1614, 1714 in FIGS. 41A-42D in that theretaining members 1832 include extension members 1855 and chamfers 1857.The extension members 1855 preferably are manipulated to move theretaining members 1832 to an open position (i.e., against the springforce holding the retaining members 1832 in the closed position). Thechamfers 1857 are operably engaged by the inclined surface 1526 of themounting member 1522 of the syringe 1512 to open the retaining members1832 and allow the syringe 1512 to be axially installed (in thedirection of Arrow E in FIG. 43C) on the syringe interface 1814. Theremaining structure of the syringe interface 1814 is substantiallysimilar or identical to the structure of the syringe interface 1714described above.

As best shown in FIG. 43E, the syringe 1512 can be installed and removedfrom the syringe interface 1814 in substantially the same manner asdescribed above with respect to FIGS. 42A-42D. In addition, however, asbest shown in FIGS. 43A, 43C, 43F and 43G, the syringe 1512 can beaxially installed and removed from the syringe interface 1814.Therefore, the syringe interface 1814 accommodates two methods ofinstalling/removing the syringe 1512.

To axially install the syringe 1512, the syringe 1512 is inserted intothe syringe interface 1814 until the mounting member 1522 engages theretaining members 1832. The inclined surface 1526 of the mounting member1522 engages the chamfers 1857 on the retaining members 1832, therebyforcing the retaining members 1832 apart against the spring force. Afterthe mounting member 1522 clears the chamfered area, the retainingmembers 1832 collapse around and capture the mounting member 1522 withinthe channels 1836 to secure the syringe 1512 to the syringe interface1814.

To axially remove the syringe 1512, the extension members 1855 of theretaining members 1832 may be manipulated (i.e., pressed together) toovercome the spring force and urge apart the retaining members 1832.When the retaining members 1832 have moved apart to such an extent thatthe mounting member 1522 of the syringe 1512 is cleared from engagementwithin the channels 1836, the syringe 1512 may be axially removed (inthe direction opposite from Arrow E) from the syringe interface 1814.

FIGS. 44A and 44B illustrate a first, slightly altered embodiment of thesyringe interface 1814 shown in FIGS. 43A-43I incorporated in or mountedon an injector head. The functionality of the syringe interface 1914 issubstantially similar or identical to that described above with respectto the syringe interface 1814.

FIGS. 45A and 45B illustrate a second, slightly altered embodiment ofthe syringe interface 1814 shown in FIGS. 43A-43I incorporated in ormounted on an injector head. The functionality of the syringe interface2014 is substantially similar or identical to that described above withrespect to the syringe interface 1814.

FIGS. 46A-46D illustrate a first preferred embodiment of a front-loadingsyringe interface and syringe system 2100 in accordance with the presentinvention. The system 2100 includes a syringe 1512 and a syringeinterface 2114. As best shown in FIG. 46A, the syringe interface 2114comprises a flexible, retaining ring 2150 disposed between a rear plate2152 and a front plate 2154. The retaining ring 2150 defines a rearledge 2160 that is adapted to engage the mounting member 1522 of thesyringe 1512 when the syringe 1512 is installed in the syringe interface2114.

The ring 2150 comprises at least one, but preferably two, releasemembers 2156 and at least one, but preferably two, protrusion members2158. Further, the ring 2150 is preferably elliptical in shape to enableengagement with and disengagement from the mounting member 1522 of thesyringe 1512, as described in more detail below. As best shown in FIGS.46B-46D, the release members 2156 protrude from the rear and frontplates 2152, 2154 for manipulation by, for example, an operator torelease the syringe 1512 from the syringe interface 2114. Further, theprotrusion members 2158 are captured by and slide within channels (notshown) defined in the rear surface (not shown) of the front plate 2154to allow removal of the syringe 1512 from the syringe interface 2114when only one release member 2156, instead of both release members 2156,can be manipulated. (The channels are described below with respect tothe alternate embodiment of FIGS. 47A-47F and are shown in FIG. 47E.)

To install the syringe 1512 on the syringe interface 2114, the syringe1512 is moved axially (in the direction of Arrow F in FIG. 46C) intoengagement with the syringe interface 2114. When the mounting member1522 engages the retaining ring 2150, the mounting member 1522 urges theflexible, elliptically-shaped ring 2150 into a more circularly-shapedconfiguration, thereby allowing the mounting member 1522 to move passthe ring 2150. After the mounting member passes the ring 2150, the ring2150 returns to its original shape, thereby capturing the mountingmember 1522 behind the rear ledge 2160 thereof and securing the syringe1512 to the syringe interface 2114.

The protrusion members 2158 and the channels (not shown) are provided tocontrol/constrain the motion of the retaining ring 2150 during syringeinstallation and removal. Specifically, the motion of the ring 2150during syringe installation and removal (i.e., from substantiallyelliptical to substantially circular, and back) is directed andcontrolled by the protrusion members 2158 being able to slide within thechannels. Consequently, regardless of the orientation of the syringe1512 during initial engagement with the retaining ring 2150, the syringeforce acting on the ring 2150 and the resulting motion of the ring 2150is directed to and constrained by the protrusion members 2158 and thechannels.

To remove the syringe 1512 from the syringe interface 2114, one or bothof the release members 2156 may be pressed inward (i.e., toward thecenter of the syringe interface 2114), thereby forcing the ring 2150from engagement with the mounting member 1522 of the syringe 1512. Whenthe release member(s) 2156 is activated, the syringe 1512 may be graspedand moved axially (in the direction opposite from Arrow F in FIG. 46C)to remove the syringe 1512 from the syringe interface 2114.

When the release members 2156 are activated, the protrusion members 2158slide within the channels (not shown) to direct the motion of the ring2150 from a generally elliptical configuration to a generally circularconfiguration to disengage the mounting member 1522 from the rear ledge2160 of the ring 2150.

As can be appreciated, the present embodiment permits a syringe 1512 tobe installed on a syringe interface 2114 with a simple, one-step, axialmotion. To remove the syringe 1512, one or both of the release members2156 may be depressed and the syringe 1512 is simply removed axiallyfrom the syringe interface 2114.

FIGS. 47A-47F illustrate an alternate embodiment 2200 of the system 2100shown in FIGS. 46A-46D. The system 2200 is substantially similar oridentical in structure and function to the system 2100 described abovein FIGS. 46A-46D, except that the release members 2256 are substantiallyenlarged for easier and simpler manipulation.

As discussed above with respect to FIGS. 46A-46D, FIG. 47E illustratesthe channels 2270 formed in the front plate 2254 and the protrusionmembers 2258 captured within the channels 2270.

FIGS. 48A-48C illustrate still another embodiment of a front-loadingsyringe interface and syringe system 2300 in accordance with the presentinvention. The system 2300 includes a syringe 2312 and a syringeinterface 2314. Unlike the syringe 1512 discussed and described abovewith respect to the other embodiments of the syringe interface andsyringe system of the present invention illustrated in FIGS. 40A-47F,the syringe 2312 preferably comprises (in addition to the othercomponents of syringe 1512) two notches 2327 defined in the rearthereof. Alternately, one, three or more notches 2327 may be defined inthe syringe 2312.

The syringe interface 2314 preferably comprises a base member 2360 and acollet member 2362 rotatably mounted in the base member 2360. Asdescribed in more detail below, the base member 2360 preferablycomprises two dowel pins 2364 inserted therein. The collet member 2362comprises a plurality of segmented members or tangs 2368 formed therein,a helical track 2370 defined in a rear end thereof and at least twoposts 2372 operable to engage the notches 2327 in the syringe 2312.Preferably, for reasons described below, small detents 2374 may beformed at suitable locations within (e.g., at or adjacent to terminalends of) the helical track 2370. The collet member 2362 is held withinthe base member 2360 by means of the dowel pins 2364, which are capturedby and ride within the helical track 2370 in the collet member 2362.

To install the syringe 2312 on the syringe interface 2314, the notches2327 on the syringe 2312 are aligned with the posts 2372 on the colletmember 2362 and the syringe 2312 is inserted axially (in the directionof Arrow G in FIG. 48B) into the collet member 2362 until the notches2327 engage the posts 2372. The syringe 2312 is then rotated (preferablyin a clock-wise direction according to Arrow H in FIG. 48B andapproximately 90°) relative to the initial syringe position to completethe installation. As the syringe 2312 is rotated, the engagement betweenthe posts 2372 on the collet member 2362 and the notches 2327 on thesyringe 2312 cause the collet member 2362 to rotate with the syringe2312 within the base member 2360.

As the collet member 2362 rotates with the syringe 2312, the dowel pins2364 riding within the helical track 2370 cause the collet member 2362to be pulled into the base member 2360. As the collet member 2362 ispulled into the base member 2360, each tang 2368 is urged by theinclined surface 2365 of the base member 2360 into engagement with themounting member 2322 of the syringe 2312, thereby securing the syringe2312 within the syringe interface 2314. As can be appreciated, the “postand notch” engagement prevents syringe rotation relative to the colletmember 2362 and the “tang and mounting member” engagement prevents axialsyringe translation.

When the syringe 2312 (and collet member 2362) are fully rotated intoplace in the base member 2360, the dowel pins 2364 snap into place inthe small detents 2374 to provide the operator with a tactile, andpossibly audible, feedback that the syringe 2312 is completely andsecurely installed in the syringe interface 2314.

To remove the syringe 2312 from the syringe interface 2314, the syringe2312 (and collet member 2362) is rotated (preferably in acounter-clockwise direction opposite from the direction of Arrow H)within the base member 2360. To initiate the rotation, sufficient forcemust be applied to the syringe 2312 (and collet member 2362) to causethe dowel pins 2364 to escape the detents 2374 and ride along thehelical track 2370. The syringe 2312 is then rotated until the dowelpins 2364 snap into place in the detents 2374 at the opposite end of thehelical track 2370. (The tactile (and possibly audible) feedback of thepins 2364 snapping into place will alert the operator that the syringe2312 may be removed from the collet member 2362.) As the collet member2362 rotates out of the “closed” position within the base member 2360,the tangs 2368 release the mounting member 2322 of the syringe 2312 andthe syringe 2312 may be removed axially (in the opposite direction ofArrow G) from the syringe interface 2314.

FIGS. 49A-49F illustrate another embodiment of an injector piston andsyringe plunger interface system 2400 of the present invention. Thesystem 2400 may be incorporated in the syringe interface and syringesystems described above. The system 2400 comprises an injector piston2402 having a piston head 2410 and a syringe plunger 2404 preferablycomprising a plunger base 2406 and a plunger cover 2408. As best shownin FIG. 49F, the plunger base 2406 and the plunger cover 2408 (which maybe formed of rubber) are preferably interconnected by means of amechanical connection.

As described below, the piston head 2410 and the plunger base 2406preferably engage one another by means of a bayonet-type, interlockingmechanism. As in know in the art, the piston 2402 is preferably disposedwithin an injector (not shown) and the plunger 2404 is preferablydisposed within a syringe, such as the syringes 1512, 2312 describedabove.

The piston head 2410 preferably comprises a pair of extending flanges2412 and, as best shown in FIG. 49E, the plunger base 2406 preferablycomprises a pair of retaining flanges 2414 separated by channels 2416.To connect the piston 2402 and the plunger 2404, the extending flanges2412 on the piston head 2410 are inserted along the channels 2416 intothe plunger 2404. When the extending flanges 2412 clear the retainingflanges 2414, which is preferably indicated by the flange 2427 on thepiston 2402 engaging the contact surface 2430 on the plunger 2404,either the piston 2402 or the plunger 2404 is rotated to cause theretaining flanges 2414 to be captured behind the extending flanges 2412.To disconnect the piston 2402 from the plunger 2404, the reverse stepsare preferably taken by the operator.

As can be appreciated by one skilled in the art, the piston 2402 and theplunger 2404 may be engaged by translating and rotating the plunger 2404(disposed within a syringe) into engagement with the piston 2402(disposed within an injector), or vice-versa. Alternately, thetranslational and rotational motions can be alternated between theplunger 2404 and the piston 2402 to interconnect the two members.

FIGS. 50A and 50B illustrate another embodiment of an injector pistonand syringe plunger interface system 2500 of the present invention. Thesystem 2500 preferably comprises a piston 2502 and a plunger 2504. Theplunger 2504 is preferably configured as shown and described above withrespect to FIGS. 49A-49F. The piston 2502 preferably comprises a pistonhead 2510 having a collet-type mechanism 2530. The collet 2530 ispreferably comprised of a plurality of flexible segment members or tangs2534.

To connect the piston 2502 and the plunger 2504, the collet mechanism2530 is inserted into the plunger 2504. When the tangs 2534 pass theplunger undercut 2536 (as best shown in FIG. 50B), preferably a rod orpin member (not shown) is driven through the center of the colletmechanism 2530 to radially force apart the tangs 2534 into lockingengagement with the plunger undercut 2536. To disconnect the piston 2502from the plunger 2504, the rod or pin member (not shown) is retractedfrom the center of the collet mechanism 2530, thereby causing the tangs2534 to disengage the plunger undercut 2536.

Due to the symmetrical nature of the collet mechanism 2530, noparticular alignment between the piston 2502 and the plunger 2504 isrequired for the piston 2502 and the plunger 2504 to engage and/ordisengage one another. This feature simplifies the installation andremoval of a syringe from a syringe interface.

As can be appreciated by one skilled in the art, the piston 2502 and theplunger 2504 may be engaged by translating the plunger 2504 (disposedwithin a syringe) into engagement with the piston 2502 (disposed withinan injector), or vice-versa.

FIGS. 51A-51C illustrate an alternate embodiment 2600 of the injectorpiston and syringe plunger interface system 2500 shown in FIGS. 50A and50B. The structure and function of the system 2600 is substantiallysimilar or identical to the system 2500 shown in FIGS. 50A and 50B,except that the collect mechanism 2630 is configured to be complementaryin shape to the plunger cover 2608 to support the plunger cover 2608during an injection procedure and to provide, for example, fluidpressure monitoring through the plunger 2604, as described in U.S. Pat.No. 5,808,203, the contents of which are hereby incorporated byreference.

FIGS. 52A-52C illustrate still another embodiment of an injector pistonand syringe plunger interface system 2700 of the present invention. Thesystem 2700 comprises a piston 2702 and a plunger cover 2708. Incontrast to the above embodiments, a plunger base is not present in theplunger 2704. Rather, the piston head 2710 is configured to becomplementary in shape to the plunger cover 2708 to support the plungercover 2708 during a fluid injection.

Preferably, as best shown in FIG. 52A, the piston 2702 comprises a basemember 2760, a sleeve 2762, a segmented flap member 2764 and a pistoncap 2766. During forward movement of the piston 2702 (e.g., during afluid injection), the piston 2702 preferably contacts and moves theplunger cover 2708 without connectively engaging or locking thereto.Upon retraction of the piston 2702 (i.e., base member 2760, flap member2764 and cap 2766), the sleeve 2762 moves (in the direction of Arrow Iin FIG. 52B) into contact with the segmented flap member 2764 and urgesthe flaps 2765 radially outward into engagement with an undercut 2767formed in the plunger cover 2708 (as best shown in FIG. 52C) to connectthe piston 2702 and plunger cover 2708 together. Retraction of thepiston 2702 and plunger cover 2708 together is useful, for example, inaspirating fluid into a syringe for subsequent injection into a patient.

FIGS. 53A-53D illustrate an alternate embodiment 2800 of the injectorpiston and syringe plunger interface systems 2600, 2700 shown in FIGS.51A-51C and 52A-52C. The function of the system 2800 is substantiallysimilar or identical to that of the systems 2600, 2700, but there aredifferent structural components that are explained below.

As best shown in FIGS. 53C and 53D, the collet mechanism 2830 is actedupon by an actuator 2870 disposed within the piston 2802 to urge thetangs 2834 radially outward into engagement with an undercut 2836 formedon the plunger cover 2808 to interconnect the piston 2802 and theplunger cover 2808. The collet mechanism preferably includes springretention members 2872, such as O-rings, to hold the tangs 2834 togetherand to spring-bias the tangs in a “disengage” position.

FIGS. 54A and 54B illustrate a current syringe plunger 2980, whichcomprises a plunger base 2984 and a mechanically-connected plunger cover2982.

FIGS. 54C and 54D illustrate an embodiment of the plunger 3080 of thepresent invention. The plunger 3080 comprises a plunger cover 3082having a larger syringe contact region (than the plunger cover 2982shown in FIGS. 54A and 54B) and a least three sealing elements 3083. Theplunger base 3084 comprises at least two flexible, piston-retentionmembers 3085, as shown and described in PCT Publication No. WO 98/20920,the contents of which are hereby incorporated by reference. The plungercover 3082 is preferably mechanically connected to the plunger base3084, as best shown in FIG. 54D.

FIGS. 54E and 54F illustrate another embodiment of the plunger 3180 ofthe present invention. The plunger cover 3182 is substantially similaror identical to the plunger cover 2982 shown in FIGS. 54A and 54B. Theplunger base 3184 comprises at least two flexible, piston-retentionmembers 3185.

FIGS. 54G and 54H illustrate an alternate embodiment of the plunger 3280of the present invention. The plunger cover 3282 is substantiallysimilar or identical to the plunger cover 2982 shown in FIGS. 54A and54B. The plunger base 3284 comprises a longer base region and at leasttwo flexible, piston-retention members 3285.

As can be appreciated, the plungers 2980, 3080, 3180, 3280 shown anddescribed above may be incorporated in the syringes 1512, 2312 describedherein.

The most preferred embodiments of the present invention will bedescribed in connection with FIGS. 55-109. Of these drawings, FIGS.55-78 concern the second preferred embodiment of the syringeinterface/release mechanism that releasably secures the syringe to theinjector housing. FIG. 79 illustrates the efficacy of the flangeassembly associated with the syringe of a related art medical injectorassembly, which applies equally to the function of the flange on thesyringe of the present invention. FIGS. 80-109 illustrate the firstpreferred embodiment of the injector piston and syringe plungerinterface system/assembly of the present invention that cooperates toaxially move the plunger within the syringe.

Among other features (as illustrated in FIGS. 55-57), the secondpreferred embodiment of the syringe interface of the present inventionencompasses a release mechanism 4010 for connecting a syringe 4012 to aninjector 4014.

Specifically, the second preferred embodiment of the present inventionprovides a mechanism by which a syringe 4012 may be connected quickly toan injector 4014 without the requirement (present in the prior art) forany particular orientation of the syringe 4012 to the injector 4014during installation. The release/connector mechanism 4010 of the presentinvention also provides an audible “click” when the syringe 4012 fullyengages the connector/release mechanism 4010. Additionally, the presentinvention provides an audible “click” when the syringe 4012 has beendisengaged from the release/connector mechanism 4010. The audible“click” for connection and removal of the syringe 4012 from therelease/connector mechanism 4010 is a particularly useful featurebecause it provides the operator with an audible confirmation of properengagement and disengagement of the syringe 4012 from therelease/connector mechanism 4010.

FIG. 55 illustrates generally the syringe interface/release mechanism4010 (hereinafter, release or connector mechanism 4010, for brevity) ofthe present invention. A rear surface 4016 of release mechanism 4010attaches to a front surface 4018 of injector 4014. A front surface 4020of release mechanism 4010 is adapted to receive a rear end 4022 ofsyringe 4012.

Release mechanism 4010 may be affixed to front surface 4018 of injector4014 in any suitable manner known to those skilled in the art. Forexample, release mechanism 4010 may be attached by means of screws (notshown) extending from the front surface 4018 of injector 4014. As wouldbe appreciated by those skilled in the art, any suitable alternativeconnection may be employed. For example, release mechanism 4010 may beaffixed by means of tabs or other suitable connectors that permitrelease mechanism 4010 to be removed from injector 4014 for cleaning ofthe components contained therein. In addition, release mechanism 4010may be adapted to mount to conventional injectors to allow syringes ofthe present invention to be used therewith.

The second preferred embodiment of the syringe interface/releasemechanism 4010, which is illustrated in FIGS. 55-78, includes aconnector housing 4024. Connector housing 4024 contains within it atleast two elements that facilitate connection of syringe 4012 toinjector 4014. The first of the two elements is a flex ring 4026, whichis disposed within release mechanism 4010 near front end 4020. Thesecond of the two elements is a rotating ring 4028, which is disposedwithin release mechanism 4010 near rear end 4016. Flex ring 4026 androtating ring 4028 are adapted to cooperate with one another, asdescribed in greater detail below, to permit connection and release ofsyringe 4012 to and from release mechanism 4010 (and, accordingly, toand from injector 4014).

FIGS. 56 and 57 illustrate release mechanism 4010 and syringe 4012 in anexploded perspective view to facilitate an understanding of this aspectof the present invention. Syringe 4012 includes a cylindrical body 4030with a tapering conical portion 4032 at a front end 4034. Conicalportion 4032 is integrally connected to a discharge end 4036. Dischargeend 4036 is provided with a luer lock 4038 that may be connected to atube (not shown) that is connected ultimately to the patient (also notshown).

As would be understood by those skilled in the art, syringe 4012 may bemade from any suitable material, such as a polymeric material.Specifically, syringe 4012 may be made of PET (polyethyleneterephthalate). Alternatively, syringe 4012 may be constructed frompolymethylpentene (which is made by Mitsui Plastics under the tradename“TPX”).

At rear end 4022, syringe 4012 includes a flange 4042, which, whensyringe 4012 is connected to release mechanism 4010, helps to preventcontrast medium that may leak from, for example, discharge end 4036 orluer lock 4038 from entering release/connector mechanism 4010. FIG. 79,which illustrates a related art syringe, helps to illustrate theadvantages provided by flange 4042 on syringe 4012.

As shown in FIGS. 55-57, a ridge 4044 is integrally formed on syringe4012 behind flange 4042 toward rear end 4022 of syringe 4012.Alternately, as shown in FIG. 123, the ridge may be segmented into twoor more sections 4044 a instead of a single continuous member. However,the sections 4044 a must collectively provide sufficient surface areaand strength to retain the syringe 4012 on the injector 4014.

As shown in FIGS. 55-57, ridge 4044 includes two parts, a slopingsection 4046 and a shoulder section 4048 that is essentiallyperpendicular to the exterior surface of cylindrical body 4030. At leastone, and preferably two or more, extending tabs or projections 4050 areprovided at rear end 4022 of syringe 4012. Tabs 4050 engage grooves 4052provided in ring 4028. Alternatively, as would be understood by thoseskilled in the art, slots, recesses or divots, etc. could be provided inrear end 4022 of syringe 4012 and tabs or projections could be providedon the interior surface of rotating ring 4028.

In addition, to mount conventional syringes on the syringe interface4010 of the present invention, a syringe adapter incorporating thestructural components (e.g., ridge 4044, tabs 4050 and/or flange 4042)of the rear end 4022 of syringe 4012 could be fashioned to fit to aconventional syringe for mounting on the injector of the presentinvention. Of course, to properly engage the conventional syringe, theadapter would preferably include structural components complementary tothe mounting elements of the conventional syringe.

Release/connector mechanism 4010 includes a front plate 4054 and a rearplate 4056. Front plate 4054 and rear plate 4056 are preferablyconstructed of aluminum coated with a fluoropolymer (such as Tufram™,which is the product name of a fluoropolymer manufactured by the GeneralMagna Plate Company). The fluoropolymer coating provides improvedresistance to wear and also provides lubricity to the exterior surfacesof front plate 4054 and rear plate 4056. Lubricity is particularlyadvantageous because, when contrast medium crystallizes on the exteriorsurface of front plate 4054 or rear plate 4056, it easily flakes off ofthe surface when the surface is coated with the fluoropolymer. Ofcourse, any suitable alternative coating material may be used on theexterior surface of front plate 4054 or rear plate 4056.

In still another alternative embodiment, a coating may not need to beapplied to the surface of front plate 4054 or rear plate 4056 if eitherplate is made of a suitable material. For example, if front plate 4054and rear plate 4056 are constructed of a high density plastic (an acetylcopolymer, for example) the material itself may provide the sameresistance to caking of contrast media as does the fluoropolymer coatingon aluminum.

As shown in FIGS. 56 and 57, front plate 4054 includes a hole 4058therethrough. A lip 4060 extends around the periphery of hole 4058through front plate 4054. In one preferred embodiment, when syringe 4012engages release/connector mechanism 4010, flange 4042 and lip 4060 matewith one another to minimize any leaked contrast medium from enteringthe interior of connector mechanism 4010 through hole 4058. FIG. 72 isparticularly illustrative of the mating engagement between lip 4060 andflange 4042. Alternatively, syringe 4012 may be constructed so that itdoes not include flange 4042, as would be understood by those skilled inthe art. In addition, some alternative structure may be provided oneither syringe 4012 or front plate 4054 to minimize ingress of contrastmedium into the interior of release/connector mechanism 4010.

In the embodiment described and illustrated throughout FIGS. 55-78,flange 4042 also serves an additional function as a mechanical stop whenit engages with front surface 4020 of front plate 4054.

Contrast medium of the type typically used within syringe 4012 mayinterfere with the operation of connector/release mechanism 4010.Accordingly, it is advantageous to include some structure, such asflange 4042 (see FIG. 79), to minimize the ingress of contrast mediuminto the interior of connector mechanism 4010. However, it is believedthat connector/release mechanism 4010 will operate even if fouled withsome contrast medium, which is usually unavoidable.

Flex ring 4026 is a substantially elliptically shaped member that isdisposed behind front plate 4054 of release/connector mechanism 4010.Flex ring 4026 may be made from an acetal copolymer or any othersuitable material. As best shown in FIGS. 66 and 67, flex ring 4026includes, on either side, a linear or flattened portion 4062 that isintegrally connected to two curved portions 4064. From approximately themidpoint of the curved portions 4064, posts 4066 extend toward rearplate 4056. As shown, flex ring 4026 includes a hole 4068 therethrough.As shown in FIG. 66, on a front side 4080 of flex ring 4026, a chamferedsurface 4082 is provided. As explained below, chamfered surface 4082facilitates insertion of rear end 4022 and ridge 4044 of syringe 4012therethrough.

In the embodiment illustrated in FIGS. 56 and 57, posts 4066 extendingrearward from flex ring 4026 are provided with bearings 4070. (Flex ring4026 is illustrated in detail in FIGS. 66 and 67.) Bearings 4070preferably are composite bearings (for example, metal and plastic)having inner and outer races with roller bearings disposed therebetween.Alternatively, bearings 4070 may be plastic elements that surround posts4066 and rotate with respect thereto. Bearings 4070 engage grooves orcam tracks 4072 on rotating ring 4028. As would be appreciated by thoseskilled in the art, however, bearings are not required for the operationof release/connector mechanism 4010. FIG. 114 illustrates one alternateembodiment of the present invention where bearings 4070 are omitted,which simplifies construction of connector mechanism 4402 and,accordingly, reduces the cost of its manufacture.

Rotating ring 4028, which is disposed to the rear of flex ring 4026within housing 4024, includes two grooves or cam tracks 4072 on a frontsurface 4074 thereof. As best shown in FIGS. 61, 68 and 69, cam tracks4072 are shaped such that the outer surface 4074 increases in diameteralong its arc from the closest point 4076 to the center of rotating ring4028 to the farthest point 4078 from the center of ring 4028. Grooves4072 engage posts 4066 through bearings 4070 and, when syringe 4012 isrotated while engaging rotating ring 4028 (e.g., to disengage syringe4012 from release/connector mechanism 4010), force posts 4066 apart tostretch flex ring 4026 in a direction indicated by arrow 4084 in FIGS.66 and 67. As shown, flex ring 4026 has a hole 4068 through its centerto accommodate rear end 4022 of syringe 4012 therein or therethrough.

Rotating ring 4028, which is shown in detail in FIGS. 68 and 69, isdisposed within an indentation or recess 4090 formed in front surface4088 of rear plate 4056. (Rear plate 4056 is shown in detail in FIGS. 70and 71.) Rear plate 4056 has a hole 4092 therethrough for accommodatingrear portion 4022 of syringe 4012. Rotating ring 4028 is disposed inindentation 4090 so that ring 4028 may freely rotate therein. Rear plate4056 has a rear surface 4094, which is illustrated in FIGS. 57 and 71.

As shown in FIGS. 57, 58 and 64, a rear surface 4096 of front plate 4054includes an indentation or recess 4098 that has essentially the sameshape as flex ring 4026. As such, indentation 4098 includes two linearor flattened portions 4100 and two curved portions 4102. (See, e.g.,FIGS. 58 and 64.) Two notches 4104 in rear surface 4096 of front plate4054 are positioned at approximately the center point of curved sections4102. Notches 4104 accommodate posts 4066 and the associated structuresthat connect posts 4066 to flex ring 4026. Indentation 4098 is shaped tobe larger than flex ring 4026 and a distance 4106 between notches 4104is greater than a distance 4108 between posts 4066 (see FIGS. 66 and 67)in their relaxed state. Notches 4104 help to prevent flex ring 4026 fromrotating within housing 4024 and permit flex ring 4026 to expand uponrotation of rotating ring 4028.

The operation of release/connector mechanism 4010 is illustrated in anddescribed by reference to FIGS. 74-78 and 55-73.

As illustrated in FIGS. 74-76, rear end 4022 of syringe 4012 is insertedinto connector housing 4024 through hole or interface 4058 in frontplate 4054, in the direction indicated by arrow 4110. Flex ring 4026sits within indentation 4098 formed in rear surface 4096 of front plate4054 so that posts 4066 engage notches 4104. Therefore, when inclinedsurface 4046 of ridge 4044 of syringe 4012 engages chamfers 4082 on flexring 4026, ridge 4044 pushes open flex ring 4026 in direction 4084(shown in FIGS. 66 and 67) from its relaxed distance 4108 (see FIG. 77)to its extended (or tensioned) distance 4106 (see FIGS. 58 and 78). FIG.75 is illustrative of this feature. Flex ring 4026 opens in thedirection indicated by arrows 4112.

After ridges 4044 clear the rear edge of flex ring 4026, the elasticnature of flex ring 4026 causes flex ring 4026 to resume its relaxedstate in the direction of arrows 4114, as illustrated in FIG. 76. Whenflex ring 4026 resumes its relaxed state, the shoulder 4048 of ridge4044 engages the rear edge of flex ring 4026. The syringe 4012 isthereby held in place by flex ring 4026 and cannot be axially removedfrom release/connector mechanism 4010. When flex ring 4026 resumes itsrelaxed state, it preferably provides an audible “click” to indicate tothe operator that the syringe 4012 has been installed on the injector.

Removal of syringe from release/connector mechanism 4010 preferablyrequires that syringe 4012 be rotated ¼ turn or an approximate onequarter turn, as described below. This operation is illustrated in anddescribed by reference to FIGS. 77, 78 and 55-73.

As illustrated in FIGS. 60 and 73, once syringe 4012 has been engaged byflex ring 4026, the two projections 4050 engage two of grooves 4052 inrotating ring 4028. FIG. 77 illustrates a cross-sectional view of theengagement of syringe 4012 and flex ring 4026 (which is shown as anentirely elliptical structure for convenience). (In alternateembodiments, one, three or more projections 4050 may be provided on thesyringe 4012.) As best shown in FIGS. 55-57, the projections 4050 arepreferably triangular in shape, with a point of the “triangle” beingdirected first into engagement with the grooves 4052 in rotating ring4028. This design allows the projections 4050 to readily align with andengage the respective grooves 4052 in the rotating ring 4028 when thesyringe 4012 is inserted into the release/connector mechanism 4010,without the operator having to joggle or twist the syringe 4012 to seatthe projections 4050.

As syringe 4012 is rotated, in a preferred embodiment, approximately onequarter turn in the counter-clockwise direction, projections 4050, whichengage grooves 4052, force rotating ring 4028 also to rotateapproximately the same amount in the same direction. While the mechanism4010 is preferably designed to release syringe 4012 by means of acounter-clockwise rotation, it is specifically contemplated thatmechanism 4010 may be adapted to release syringe 4012 by means of aclockwise rotation. (It should be noted that the one-quarter turn towhich reference is made herein is not intended to mean exactly onequarter of a turn. The term “one quarter turn” is meant to indicate aturn that is about one quarter turn and preferably in a range from 45 to90 degrees from the rest position of syringe 4012. Alternately, anysuitable range of rotation may be used to facilitate disengagement ofthe syringe 4012 from mechanism 4010.)

Because posts 4066 (with bearings 4070) of flex ring 4026 engage andride along cam tracks 4072 on rotating ring 4028, the rotation of ring4028 will urge flex ring 4026 from its relaxed (i.e., syringe engaged)state to its extended (i.e., syringe disengaged) state. As posts 4066travel along cam tracks 4072 from the inner-most position 4076 to theoutermost position 4078, flex ring 4026 is stretched from the relaxeddistance 4108 to the extended distance 4106 (in the direction of Arrows4112), at which point the rear edge of flex ring 4026 disengages theshoulder 4048 of syringe 4012. Consequently, the syringe 4012 isdisengaged and may be axially removed from flex ring 4026 and mechanism4010. When the syringe 4012 is removed from the mechanism 4010, thespring force of the flex ring 4026 urges the posts 4066 to travel alongthe cam tracks 4072 from the outer-most position 4078 to the inner-mostposition 4076, thereby returning the flex ring 4025 to its relaxed statefor receipt of a new syringe. In addition, when the syringe 4012 isdisengaged from the flex ring 4026, the operator preferably hears asecond audible “click” to indicate that the syringe 4012 has beendisengaged from the mechanism 4010 (and, accordingly, the injector).

A third preferred embodiment of the syringe interface/release mechanismis shown in FIGS. 124 and 125. Because the third preferred embodiment issimilar in function and structure to the second preferred embodimentillustrated in FIGS. 55-78, for ease of reference the same referencenumerals have been used to identify the respective components thereof.The differences between the second and third preferred embodiments arediscussed below. The third preferred embodiment shown in FIGS. 124 and125 includes a pair of return springs 4091 to assist flex ring 4026 androtating ring 4028 to return to their rest state after syringe 4012 isreleased from release/connector mechanism 4010. (Optionally, bearings4093 may be provided for springs 4091. These bearings may be retained inrear plate 4056 by pins (not shown) and formed of Delring.) In thisembodiment, the return springs 4091 are disposed between the rotatingring 4028 and the rear plate 4056. However, the return springs 4091 maybe connected between rotating ring 4028 and the front plate 4054 ofhousing 4024. The rotating ring 4028 preferably includes a pair ofprojecting tabs 4095 to which the free ends 4097 of the springs 4091 areconnected. As shown, the springs 4091 preferably ride within and areconstrained by a pair of complementary shaped recesses 4099 formed inthe rear plate 4056. The return springs 4091 are preferably ¾″ constantforce springs provided by Associated Spring Raymond. The return springs4091 are especially useful in assisting the flex ring 4026 and therotating ring 4028 to return to their rest state if the elements ofsyringe interface/connector mechanism 4010 have become fouled withcontrast media during the medical procedure (or over time after repeateduse).

As discussed above, FIG. 79 illustrates the efficacy of flange 4042 forpreventing contrast media in syringe 4012 from entering a syringeinterface and injector of the present invention.

The present invention also includes a construction for a first preferredembodiment of an injector piston and syringe plunger interface assembly4200 for injector 4014 that engages a plunger within syringe 4012without regard to the orientation of syringe in release/connectormechanism 4010 or the orientation of the plunger within the syringe4012. FIGS. 80-109 are illustrative of piston/plunger assembly 4200 andits operation.

Piston/plunger assembly 4200 is positioned movably in an axial relationto injector 4014 and syringe 4012. As shown in FIGS. 85 and 86, piston4202 includes a rear end 4204 and a front end 4206. Piston 4202 alsoincludes an elongated shaft 4208 extending between rear end 4204 andfront end 4206. Rear end 4204 of piston 4202 is connected to a mover ormotor drive train within injector 4014. The mover may be any type ofmover suitable for moving piston 4202 axially into and out from injector4014, including a motor and drive train combination.

As shown in FIGS. 80-82, a piston sleeve 4210 surrounds shaft 4208 ofpiston 4202. Piston sleeve 4210 is freely movable with respect to piston4202. In other words, piston sleeve 4210 is not connected to piston4202. Piston sleeve 4210 is essentially a cylindrical tube with a frontend 4212 and a rear end 4214. (See FIG. 87 for an enlarged detail ofpiston sleeve 4210.)

A collar 4216 is disposed at front end 4212 of piston sleeve 4210. Asshown in FIGS. 88-90, collar 4216 includes a hole 4218 through whichpiston 4202 is disposed. An annular flange 4219 is provided on a rearside 4220 of collar 4216 for engagement of front end 4212 of pistonsleeve 4210. A second annular flange 4222 is provided on a front surface4224 of collar 4216. Annular flange 4222 engages a plunger cap 4226,which is generally depicted in FIGS. 97-100.

Plunger cap 4226 has a base portion 4230 that extends outwardly from abase thereof. (See FIGS. 97-100.) The base portion 4230 is connected toa frusto-conical section 4232 that tapers inwardly toward a centerlineof plunger cap 4226. An annular groove 4234 is provided in plunger cap4226 near frusto-conical section 4232. Slots 4236 are disposed withinannular groove 4232 for retaining support ring grippers 4238. A topportion 4240 of plunger cap 4226 extends upwardly from annular groove4234. Top portion 4240 is cone shaped and terminates in a rounded tip4242. As illustrated in FIG. 98, plunger cap 4226 is essentially ahollow body that defines an interior volume 4244.

Front end 4206 of piston 4202 extends into interior volume 4244 ofplunger cap 4226. As shown in FIGS. 107 and 108, front end 4206 ofpiston 4202 is connected to gripper expander 4246. Gripper expander 4246is connected to front end 4206 of piston 4202 by any suitable means suchas a screw (not shown) disposed through a hole 4248 that extends throughthe center of gripper expander 4246. (Detailed illustrations of gripperexpander 4246 are provided in FIGS. 91-93.)

Gripper expander 4246 has a top surface 4250 and a bottom surface 4252.From top surface 4250, gripper expander 4246 tapers inwardly to form afrusto-conical section 4254. A cylindrical section 4256 extends fromfrusto-conical section 4254 to bottom surface 4252. When connected tofront end 4206 of piston 4202, gripper expander 4246 forms a T-shapedstructure with piston 4202, as illustrated in FIGS. 107 and 108.

As illustrated in FIGS. 83, 84, 94-96, 107 and 108, support ringgrippers 4238 extend through the slots 4236 in annular groove 4234 ofplunger cap 4226. Support ring grippers 4238 are designed to extendoutwardly from annular groove 4234 when piston/plunger assembly 4200 ismoved in a rearward direction or retracted (into injector 4014). Asshown in FIGS. 94-96, support ring grippers 4238 have a body 4258 thatis L-shaped in cross-section. On an interior edge 4260, support ringgrippers 4238 are provided with a chamfer 4262 that engages withfrusto-conical surface 4254 on gripper expander 4246. When gripperexpander 4246 moves in the direction of injector 4014, which isindicated by arrows 4264 in FIG. 108, support ring grippers 4238 moveoutwardly from plunger cap 4226 in the direction of arrows 4266 (alsoshown in FIG. 108).

A rubber cover 4268 (which is shown in detail in FIGS. 105 and 106) isusually assembled with syringe 4012 and is located therein. Movement ofrubber cover 4268 causes the liquid contained in syringe 4012 to bepushed out through the discharge end 4036 and into the patient. Rubbercover 4268 includes a conically shaped top 4270 with a substantiallycylindrical 4272 portion extending rearwardly therefrom. Cylindricalportion 4272 may include any number of ridges 4274 and grooves 4276 thatmay be required for a particular application to assure that the liquiddoes not pass by the plunger and leak out of the syringe 4012 during,for example, an injection procedure.

The interior of rubber cover 4268 is hollow and, as a result, has aconical inner surface 4278. In addition, at a bottom end 4280, a lip4282 is provided that defines a circular opening 4284 into the interiorof rubber cover 4268. Lip 4282 is designed to be engaged by a rubbercover support ring 4286.

Rubber cover support ring 4286, which is shown in detail in FIGS.101-104, is constructed of a suitable plastic material. Rubber coversupport ring 4286 engages lip 4282 on the interior of rubber cover 4268and provides additional rigidity to rubber cover 4268. Rubber coversupport ring 4286 includes an annular ring 4288 at a bottom portion 4290thereof. A groove 4292 is provided above annular ring 4288 forengagement of lip 4282 of rubber cover 4268. A frusto-conical section4294 extends upwardly from groove 4292 and mates within the interiorsurface 4278 of the rubber cover 4268. A hole 4296 extends throughrubber cover support ring 4286. The interior surface of rubber coversupport ring 4286 includes a lip 4298 with a chamfered surface 4300. Lip4298 serves as a location for engagement by support ring grippers 4238.

In an alternate embodiment of rubber cover 4268, rubber cover supportring 4286 may be eliminated altogether. The alternate embodiment of therubber cover, which is designated 4306, is illustrated in FIGS. 110-113.Since rubber cover 4306 does not include rubber cover support ring 4286,rubber cover 4306 is thicker in cross-section than rubber cover 4268. Sothat grippers 4238 may engage rubber cover 4306 during at least aretraction operation of injector 4014, rubber cover 4306 includes a lip4308 on an interior surface.

Rubber cover 4306 has essentially the same shape as rubber cover 4286.Rubber cover 4306 includes a conically shaped top portion 4310 with arounded tip 4312. At its lower end 4314, rubber cover 4306 includesthree ribs 4316 and two grooves 4318 positioned along a cylindricalportion. The interior of rubber cover 4306 defines an interior volume4320 with tapered sides 4322. Rubber cover 4306 is thicker than rubbercover 4286 so that it has added strength and sealing capabilities (i.e.,to the interior of syringe 4012).

The operation of piston/plunger assembly 4200 will now be described inconnection with FIGS. 107-109. The operation of piston/plunger assembly4200 does not differ substantially if rubber cover 4268 (together withrubber cover support ring 4286) or rubber cover 4306 are employed withinsyringe 4012.

When the operator of injector 4014 desires to advance or push thepiston/plunger assembly 4200 forward, he may push one of the buttons4302 on injector 4014 to actuate forward movement of piston 4202.Movement of piston 4202 in the forward direction pushes rubber cover4268 in the forward direction. Because forward movement of rubber cover4268 in the forward direction does not require any connection betweenpiston assembly 4202 and rubber cover 4268, the two are only in a matingengagement with one another. However, if the operator of injector wishesto retract or move rubber cover 4268 in the rearward direction,piston/plunger assembly 4200 must grab onto rubber cover 4268 to pull ittoward injector 4014.

To grab onto rubber cover 4268 (and its associated rubber cover supportring 4286, where included), grippers 4238 extend outwardly to grab ontolip 4298 of rubber cover support ring 4286. If the alternative rubbercover 4306 is used, grippers 4238 engage lip 4308. The engagement of lip4298 (or alternatively lip 4308) by grippers 4238 is described below.

As mentioned above, piston sleeve 4210 is not connected to piston 4202.Instead, it is freely moveably (in the axial direction) with respect topiston 4202. Within injector 4014, there is an oring 4304 that matinglyengages the exterior surface of piston sleeve 4210. (See FIGS. 107 and108.) Accordingly, when piston 4202 is withdrawn into injector 4014,piston sleeve 4210 experiences a frictional engagement with o-ring 4304that tends to hold piston sleeve 4210 in place. In other words, ring4304 biases piston sleeve 4210 in a forward direction when piston 4202is retracted in a rearward direction.

Because piston 4202 is connected to gripper expander 4246, as piston4202 moves into injector 4014, so does gripper expander 4246. However,piston sleeve 4210, collar 4216, and plunger cap 4226, which are theelements connected to one another, are biased in a forward direction byO-ring 4304. Accordingly, when actuated, piston 4202 and gripperexpander 4246 move rearward in relation to piston sleeve 4210, collar4216 and plunger cap 4226. Frusto-conical section 4254 of gripperexpander 4246 is then caused to engage chamfered regions 4262 to forcegrippers 4238 outwardly through slots 4236 in plunger cap 4226, as shownby Arrows 4266 in FIG. 108, and into engagement with lip 4298 (or lip4308) of support ring 4286. To hold grippers 4238 in place, a rubbersheath (not shown) may be placed over plunger cap 4226. The rubbersheath may also assist in preventing contrast medium from enteringplunger cap 4226 through slots 4236.

By this construction, then, rubber cover 4268 connectively engagespiston 4202 only when piston 4202 is retracted or moved in a rearwarddirection into or toward injector 4014. When stationary or when movingforward, rubber cover 4268 does not engage piston 4202 so that syringe4012 may be easily disengaged from syringe interface 10.

As can be appreciated, the piston/plunger assembly 4200 of the presentinvention is preferably not orientation specific. That is, engagementbetween the piston 4202 and the plunger cover 4268 can occur withoutregard to the orientation of the plunger within the syringe 4012 and/orthe orientation of the plunger with respect to the piston 4202. Inconjunction with suitable syringe interfaces of the present invention,injector and syringe systems are provided that do not require anoperator to orient the syringe in any particular manner with respect tothe injector to mount the syringe thereon. The present invention, in atleast one aspect, thereby improves and facilitates the mounting andinstallation of syringes on injectors.

FIG. 114 illustrates an alternate embodiment of the release/connectormechanism 4402 of the present invention. Here, flex ring 4026 does notinclude bearings 4070 around posts 4066. As mentioned above, thissimplifies the construction of connector mechanism 4402. Here,release/connector mechanism 4402 operates in the same manner asconnector mechanism 4010 except that posts 4066 engage cam tracks 4072directly. For convenience, screws 4404 are shown that hold front plate4054 to rear plate 4056.

FIG. 115 illustrates another embodiment of the syringeinterface/connector mechanism 4406 of the present invention. Here,rotating ring 4028 has been eliminated altogether. In this embodiment,grooves 4408 are provided on an inner surface of flex ring 4410 forengagement with projections 4412 on syringe 4414 (see FIG. 117). Posts4416 extend from upper and lower positions on flex ring 4410 and engagegrooves 4418 in back plate 4420 (or, alternatively, in the front plate(not shown)). When syringe 4414, which is illustrated in cross-sectionin FIG. 117, is rotated (preferably in a counter-clockwise direction),projections 4412 rotate flex ring 4410 so that posts 4416 travel ingrooves 4418 to stretch flex ring 4410 and release syringe 4414. For thebarrel projections 4412 to engage grooves 4408, the projections 4412 arepositioned between ridge 4044 and flange 4042. So that the differencesbetween the two alternative designs may be evaluated, syringe 4414 isillustrated adjacent syringe 4012 (see FIGS. 116 and 117).

FIG. 118 illustrates three alternate embodiments of the different shapesfor grooves for rotating ring 4028 or flex ring 4410. It should be notedthat the different shapes for grooves 4052 may be used with anyalternative embodiment of rotating ring or flex ring described herein.First, in embodiment #1, grooves 4052, which are the same as thosedepicted in FIG. 59, are illustrated. In embodiment #1, grooves 4052 aresemi-cylindrical indentations on the inner surface of rotating ring4028. Embodiment #2 illustrates grooves 4052′ that are triangularlyshaped. Embodiment #3 illustrates that grooves 4052″ are U-shaped. Thoseskilled in the art should readily recognize that grooves 4052, 4052′,4052″ may be of any suitable shape to engage projections 4050 or theirequivalent.

One possible disadvantage of the previously described embodiments of thesyringe interface/connector mechanism of the present invention is madeapparent by the illustrations in FIGS. 77 and 78. There, it can beobserved that flex ring 4026 engages ridge 4044 on syringe 4012 at onlytwo locations 4400 around the periphery of syringe 4012. While thisworks in most instances to hold syringe 4012 in place, there are someinstances where high pressure must be applied to inject contrast mediumin syringe 4012 into a patient. Where high pressure (e.g., pressure ator above 1000 p.s.i.) is applied, the two regions 4400 may not provideenough contact area with ridge 4044 to hold syringe 4012 securely inrelease/connector mechanism 4010. In these instances, it is preferredthat flex ring 4026 contact most, if not all, of ridge 4044 around thecircumference of syringe 4012.

FIG. 119 illustrates an embodiment of the release/connector mechanism4440 of the present invention that offers a flexible ring 4450 that iscircularly shaped to engage a significant portion of ridge 4044 alongthe periphery of syringe 4012. Flexible ring 4450 is nearly a completecircle with an inner diameter, in a relaxed state, that is just largerthan the outer circumference of syringe body 4030. Flexible ring 4450includes two posts thereon, post 4452 that engages a hole 4456 in agroove 4460 in front plate 4462 and another post 4454 that fits into ahole 4458 in rotating ring 4464. Rotating ring 4464 is nested in anindentation (not shown) in back plate 4466. Screws 4468 may be used toassemble release/connector mechanism 4440.

As with other embodiments, syringe 4012 is inserted through hole 4470 infront plate 4462. When ridge 4044 of syringe 4012 clears flex ring 4450,flex ring 4450 snaps into place around syringe 4012 and provides anaudible “click”. When in place, projections 4050 on syringe 4012 engagegrooves 4472 on the interior surface of rotating ring 4464.

To disengage syringe 4012 from release/connector mechanism 4440, syringe4012 is rotated approximately one-quarter turn. The rotation of syringe4012 causes rotating ring 4464 to turn in the direction of arrow 4474.As rotating ring 4464 turns, pressure is applied to post 4454 to causeflex ring 4450 to enter a tensioned state where it has a larger innerdiameter. When a sufficient amount of force has been applied to flexring 4450, it releases syringe 4012 and provides an audible “click” upondoing so.

In the previous embodiments, the flex ring has been shown as a singlepiece construction. It is possible, however, that flex ring could beconstructed from several pieces that are connected in a manner to oneanother or to the housing for the release/connector mechanism so thatthe separate elements have a relaxed and a tensioned state (as does thesingle piece construction).

One possible embodiment of a two-piece “flex ring” is illustrated inFIG. 120. As shown, syringe interface/connector mechanism 4480 includesa front plate 4482 that is similar in design to front plate 4054 (shownin FIGS. 56 and 57). Front plate 4482 includes an indentation 4484 in arear surface thereof that is sized to accommodate flex ring 4486. Frontplate 4482 has a hole 4488 therethrough. It also has notches 4490 thataccommodate posts 4492 on flex ring 4486.

Flex ring 4486 is shaped similarly to flex ring 4026. As shown, flexring 4486 has two separate arcuate pieces 4494, 4496 that are connectedtogether along seams 4498, 4500 on either side. Two springs 4502, 4504are located on either side of flex ring 4486 to bias flex ring 4486 intoa relaxed position around syringe 4012 once inserted therethrough.

A rotating ring 4506 is positioned behind flex ring 4486. Rotating ring4506 has a hole 4508 therethrough and is provided with a number ofgrooves 4510 in its inner surface. Rotating ring 4506 is not connecteddirectly to flex ring 4486 (as with other embodiments). Instead,rotating ring 4506 includes two posts 4512, 4514 that extend from a rearsurface through rear plate 4516. As with other embodiments, rotatingring 4506 is positioned within an indentation (not shown) on the innersurface of rear plate 4516.

Two semicircular arms 4518, 4520 are positioned behind rear plate 4516.Each arm includes a post 4522, 4524 that engages posts 4492 on flex ring4486. Each arm also includes a notch 4526, 4528 that engages a post4512, 4514 on rotating ring, respectively.

The operation of release/connector mechanism 4480 is essentially thesame as with previous embodiments. When syringe 4012 is inserted throughflex ring 4486, the two segments 4494, 4496 of flex ring 4486 springapart into a tensioned state until ridge 4044 on syringe 4012 clears therear edge of the segments 4494, 4496 of flex ring 4486. When ridge 4044clears flex ring 4486, springs 4502, 4504 return to a relaxed state anddraw segments 4494, 4496 into engagement with syringe 4012. Whensegments 4494, 4496 return to a relaxed state, they preferably providean audible “click”.

To remove syringe 4012 from release/connector mechanism 4480, syringe4012 is rotated approximately one-quarter turn. As before, syringe 4012is provided with projections 4050 that engage grooves 4510 on theinterior surface of rotating ring 4506. As rotating ring 4506 is turned,arms 4518, 4520 move outwardly from a relaxed position to a tensionedposition and apply pressure to posts 4492 to urge segments 4494, 4496 offlex ring 4486 apart. Once the syringe is rotated a sufficient distance,segments 4494, 4496 are sufficiently separated from one another torelease syringe 4012, preferably with an audible “click”.

FIGS. 121 and 122 illustrate one further example of a release/connectormechanism 4550 according to the teachings of the present invention.Here, instead of providing a flex ring, four segments 4552, 4554, 4556,4558 are provided around the periphery of the common hole 4560 throughconnector mechanism 4550. The four segments 4552-4558 may be biased byany suitable mechanism. For example, segments 4552-4558 may be connectedto a rotating ring by arms in a similar manner as connector mechanism4480.

In addition, a front-loading syringe 4612 incorporating syringe encodingis shown in FIG. 126. Syringe 4612 includes a cylindrical body 4630 witha tapering conical portion 4632 at a front end 4634. Conical portion4632 is integrally connected to a discharge end 4636.

At rear end 4622, syringe 4612 includes two encoding rings 4641, aflange 4642 (which, when syringe 4612 is connected to release mechanism4010, helps to prevent contrast medium that may leak from, for example,discharge end 4636 from entering release/connector mechanism 4010), anattachment ridge 4644, and preferably two or more, extending releasetabs or projections 4650. The rings 4641 preferably extend around thecircumference of syringe 4612, but the rings 4641 may be segmented ifdesired. Also, while two rings 4641 are shown, one, three or more rings4641 may be provided on syringe 4612 to accommodate varying encodingrequirements. The structure and function of the encoding system isdescribed in U.S. application Ser. No. 09/765,498, filed on Jan. 18,2001, and assigned to the Assignee of the present application, thecontents of which are hereby incorporated by reference.

The present invention also provides injectors and injector systemshaving certain “automated” or “auto” features that facilitate theoperation thereof. The auto features of the present invention can befully automatic, require operator initiation, and/or require some degreeof operator, intervention, oversight and/or control. For example, theinjectors and injector systems of the present invention may be providedwith one or more of the following functions: “auto advance,” “autoengage,” “auto fill,” “auto prime” and “auto retract.” Each of thesefunctions, together with their attendant advantages and benefits, isdescribed below in more detail in conjunction with empty, preloadedand/or prefilled syringes. As known in the art, “empty” syringes aresyringes that do not contain fluid when mounted on an injector for aninjection procedure. Empty syringes typically come in two forms:“plunger-rearward” syringes and “plunger-forward” syringes.Plunger-rearward syringes are syringes having plungers that areinitially located at the rearward or proximal ends thereof.Plunger-forward syringes are syringes having plungers that are initiallylocated at the forward or distal ends thereof. “Preloaded” syringes areempty syringes that have been filled with fluid (e.g., by hand or by useof an injector to aspirate fluid into the syringe) prior to an injectionprocedure, and then stored for subsequent use on an injector for theinjection procedure. “Prefilled” syringes are syringes that have beenfilled with fluid prior to delivery to the customer.

In a preferred embodiment, the injectors and injector systems of thepresent invention are adapted to automatically identify, for example,the types, sizes, fluid contents (if applicable) and configurations ofsyringes mounted thereon. Suitable sensors and encoding devices arediscussed above and in U.S. Pat. No. 5,383,858 and PCT Publication No.WO 99/65548 (both of which are incorporated herein by reference) todifferentiate between varying syringes (e.g., empty, preloaded orprefilled syringes) used on injectors. These sensing schemes, orsuitable alternatives as known in the art, could also be used toimplement the auto features discussed below.

The “auto engage” feature allows an injector to automatically advancethe drive piston thereof to engage a syringe plunger upon installationor attachment of the syringe to the injector. In a preferred embodiment,the auto engage feature occurs without operator intervention. Thisfeature is particularly useful for preloaded and prefilled syringes,which typically have plungers located at some position within thesyringe barrel other than at the proximal and distal ends thereof, andplunger-forward syringes. In the case of prefilled syringes, the autoengage feature automatically connects the injector piston and syringeplunger for subsequent priming of the syringe (and associated tubing)and subsequent injection. For plunger-forward syringes, the auto engagefeature engages the piston and plunger for subsequent retraction of theplunger for aspiration of fluid, such as contract media, into thesyringe.

One embodiment of an auto-engage or auto-dock feature is described inconnection with FIGS. 127A through 127C, which illustrate a “dual”injector 5500 to which an adapter 5600 and a syringe 5900 are attached.As best shown in FIG. 127B, syringe 5900 includes a flange 5905 whichcooperates with front-loading injector 5500 to removably attach syringe5900 to injector 5500. In that regard, flange 5905 cooperates with asyringe interface 5502, which includes a flex ring 5504 that forms anabutting and releasable connection with syringe flange 5905 in a mannerdescribed above. Similarly, as best shown in FIG. 127C, adapter orconnector 5600 includes a flange 5605 which cooperates with a syringeinterface 5502′ of injector 5500 including a flex ring 5504′ that formsan abutting and releasable connection with flange 5605.

Syringe 5900 also includes a plunger 5910 that has a generally annularrear base member 5912 and a forward elastomeric cover 5916 attachedthereto. A forward surface of piston 5520 is preferably shaped toconform generally to the shape of the inner surface of plunger cover5916.

A rear section of syringe 5900 can, for example, include indicators suchas grooved rings 5920 a, 5920 b and 5920 c (see, for example, FIG. 127B)that cooperate with a light source 5510 and sensors 5512 a, 5512 b and5512 c of sensors 5512 a-e to provide information (via, for example, abinary code) about the configuration of syringe 5900 as described inU.S. patent application Ser. No. 09/796,498, the disclosure of which isincorporated herein by reference. The control system of injector 5500can thereby be signaled or alerted that syringe 5900 is connectedthereto and the operation of injector 5500 can be controlled accordingto the configuration of syringe 5900.

As used herein, the term “syringe configuration” is used to encompassany or all information about a particular syringe (including syringesused with an intervening adapter), including, but not limited to,information about the mechanical properties of a syringe (for example,material, length and diameter) as well as information about the contentsof the syringe (for example, volume and composition). With the advent ofnew syringes, and especially prefilled syringes, the need to accuratelyencode and sense (or read) syringe configuration variables isheightened. The syringe configuration information can be used by apowered injector to control the injection procedure as a function ofdefined syringe configuration/injection parameters. Moreover, a recordof data associated with an injection procedure may be kept, for example,to satisfy accurate billing and cost information requirements undermanaged health care. A record may be maintained of information such asthe type of syringe used, the amount of contrast medium used, the typeof contrast medium used, the sterilization date, the expiration date,lot codes, the properties of the contrast media, and/or other clinicallyrelevant information. Such information can be recorded digitally forsharing with computerized hospital billing systems, inventory systems,control systems, etc.

Referring, for example, to FIG. 127B, as piston 5520 is advanced towardplunger 5910 a biased (for example, spring-loaded via spring 5574)sensing pin 5570 contacts the rearward or inward surface of plungercover 5916. Pin 5570 is forced rearward to so that it impinges upon thefield of sensor 5578 (for example, an optical sensor). Sensor 5578 cansignal the control system of injector 5500 so that the control systemstops advancement of piston 5520 after a predetermined amount of time ordistance of advancement of piston 5520, so that piston 5520 is broughtinto engagement with plunger 5910, but advancement of piston 5520 isstopped before movement of syringe plunger 5910. The amount of timebetween such a signal and the cessation of piston movement can, forexample, depend on compliance or tolerance within the piston drivemechanism as well as the type of syringe attached to interface 5502.

Piston 5520 preferably includes retractable pins 5580 that form anabutting connection with one or more ledges, flanges or grooves 5918formed around the interior circumference of plunger base 5912 whenpiston 5520 is to be retracted, thereby causing syringe plunger 5910 toretract or move rearward along with piston 5520. In FIGS. 127A and 127B,pins 5580 on piston 5520 are, for example, shown extended to form aconnection with plunger 5910 of syringe 5900.

During advancement of piston 5520 to engage plunger 5910 as well asduring advancement of piston 5520 to advance plunger 5910 within syringe5900 (for example, to expel air or fluid contained within syringe 5900),pins 5580 are preferably in a retracted state (as, for example,illustrated for pins 5580′ in FIGS. 127A and 127C). If retraction ofplunger 5910 is desired, pins 5580 are extended to abut ledge 5918.

In the embodiment of FIGS. 127A through 127C, piston 5520 includes anouter piston section having a rear outer piston sleeve 5530 and forwardplunger abutment section 5540 attached thereto. Abutment of a forwardfacing flange or ledge 5546 of abutment section 5540 with a rear surfaceof plunger base 5912 causes plunger 5910 to move forward within syringe5900 with forward movement of piston 5520.

Piston 5520 also includes an inner piston section including a rear innerpiston member 5550 and a forward inner member 5560 attached thereto. Theinner piston section is movable or slidable in an axial directionrelative to the outer piston section to control the state or position ofpins 5580. The motion of the inner piston section relative to the outerpiston section is preferably limited. For example, such relative motioncan be limited using a pin fixed to rear inner piston member 5550. Thepin passes through and seats within a slot formed in rear outer pistonsleeve. FIG. 127C illustrates, for example, a pin 5552′ which isattached to inner piston member 5550′ and passes through an elongatedslot 5532′ of outer piston sleeve 5530′ of piston 5520′. Pistons 5520and 5520′ are generally identical in construction and operation and likecomponents are numbered herein similarly with a “′” designation added tothe components of piston 5520′.

Pins 5580 are positioned to extend and retract in a radial directionthrough passages 5542 formed in plunger abutment section 5540. Duringadvancement of piston 5520, friction between outer piston sleeve 5530and an adjacent wall of injector 5500 causes inner piston member 5550and forward inner member 5560 to move forward relative to outer pistonsleeve 5530 and plunger abutment section 5540 for a distance determinedby the cooperation of a pin 5552 (not shown, but identical to pin 5552′)and a passage 5532 (not shown, but identical to passage 5532′)). Oncepin 5552 abuts the forward edge of passage 5532, the outer section andthe inner section of piston 5520 will advance together. During theforward movement of forward inner member 5560 relative to plungerabutment section 5540, sloped surfaces 5564 of inner member 5560 contactpins 5580 and cause pins 5580 to be in the retracted state illustrated(see, for example, pins 5580′ in FIGS. 127A and 127C).

During retraction of piston 5520, as illustrated, for example, in FIGS.127A and 127B, the inner section of piston 5520 moves rearward relativeto the outer section of piston 5520 for a distance determined by thecooperation of pin 5552 and passage 5532. During the rearward movementof forward inner member 5560 relative to plunger abutment section 5540,sloped surfaces 5568 of inner member 5560 contact pins 5580 and causepins 5580 to be in the extended state illustrated, for example, in FIGS.127A and 127B. Plunger 5910 is retracted with further rearward movementof piston 5520 as a result of the abutment of pins 5580 with ledge orflange 5918.

A second syringe generally identical to syringe 5900 can be attached tointerface 5510′ of injector 5500. Moreover, a number of other types ofsyringes can be attached to either or both of interfaces 5502 and 5502″through use of adapters as known in the art.

Referring to FIGS. 127A and 127C, for example, a syringe cradle 5610 ofadapter 5600 provides for attachment of a syringe 5700 including asyringe plunger 5710 and a cooperating extending plunger pushrod 5720 toinjector 5500. A rear portion of adapter section 5600 can, for example,include indicators such as grooved rings 5620 a, 5620 b and 5620 d thatcooperate with a light source 5510′ and sensors 5512 a′, 5512 b′ and5512 d′ of sensors 5512 a′-e′ to provide information (via, for example,a binary code) about the configuration of adapter 5560 and syringe 5700as described above. The control system of injector 5500 can thereby besignaled or alerted that adapter 5600 is connected thereto and theoperation of injector 5500 can be controlled accordingly.

Adapter 5600 further includes a syringe interface or connector 5630 at aforward end thereof to attach syringe 5700 via, for example, cooperationwith a rear flange 5730 of syringe 5700. Adapter 5600 preferably furtherincludes a plunger extension carriage 5800 that can form a removableconnection with piston 5520′ of injector 5500. In that regard, carriage5800 includes a plunger interface or connector on a rear section thereofthat cooperates with piston 5520′ to form a releasable connectiontherewith. As known in the art, many types of interfaces or connectorscan be used to connect an injector piston to a plunger or adapter. See,for example, U.S. Pat. Nos. 5,520,653 and 6,336,913, the contents ofwhich are incorporated herein by reference.

Referring, for example, to FIG. 127C, carriage 5800 is, for example,maintained in a rearward position within cradle 5610 by abutment with abiased (for example, spring-loaded) abutment member 5640 (for example, aspring-loaded ball) disposed in passage formed in cradle 5600. As piston5520′ is advanced in a forward direction, a surface 5546′ of plungerabutment member 5540′ contacts carriage 5800 at a rear surface thereof.Further forward motion of piston 5520′ causes carriage 5800 to moveforward of (i.e., to overcome the biasing force of) abutment member 5640so that a biased contact member 5810 of carriage contacts the rearwardsurface of flange 5724 formed on a rearward end of plunger extension5720. Preferably the forward surface of contact member 5810 is of asufficient diameter that it will abut a rearward surface of flange 5724even if a hole or passage is formed in the rear surface thereof as isthe case with many types of syringes. As piston 5520′ is advanced,contact member 5810 moves rearward causing biased sensing pin 5570′ tomove rearward. Eventually, a sensor 5578′ senses the rearward movementof pin 5570′ relative to sensor 5578′ and the control system of injector5500 can be alerted that carriage 5800 is connected or near connectionto plunger extension 5720.

In that regard, carriage 5800 further includes a plunger extensionconnector to form a releasable connection with plunger extension 5720 ofsyringe 5700. In the embodiment of FIGS. 127A through 127C, carriage5800 includes two capture members 5830 that flex radially outward toform a releasable connection with flange 5724 of plunger extension 5720.

In one embodiment, sensor 5578′ signals the control system of injector5500 a known amount of time before flange 5724 is seated in capturemember 5830 so that the control system stops advancement of piston 5520′after a secure connection is made between carriage 5800 and plungerextension flange 5724, but before piston 5520′ is advanced to a degreeto cause injection of fluid from the interior of prefilled, preloaded orempty syringe 5700. Preferably, the axial force required to engagecapture members 5830 with flange 5724 is less than the static frictionof syringe plunger 5710 within syringe 5700 so that engagement ofcapture members 5830 with flange 5742 does not cause movement of syringeplunger 5710. The amount of time or distance of piston movement after asignal is received by the injector control system before the advancementof the piston is stopped can be automatically adjusted in accordancewith the sensed syringe/adapter configuration.

Piston 5520′ includes retractable pins 5580′ (which operate in themanner described above for pins 5580). In that regard, pins 5580′ forman abutting connection with one or more ledges, flanges or grooves 5840formed at a known axial position around the interior circumference ofsyringe carriage 5800 when piston 5520′ is to be retracted to drawcarriage 5800 rearward. Capture members 5830 maintain a connection withflange 5724 to draw plunger extension 5720 rearward when piston 5520′ isretracted.

The “auto advance” feature is related to, and may be considered a typeor subset of, the auto engage feature as, for example, described above.The auto advance feature allows an injector to automatically advance theplunger of a plunger rearward syringe (i.e., by the drive piston of theinjector) to the distal end of the syringe after the syringe isinstalled on the injector. This feature operates to expel air from anempty, plunger-rearward syringe and to place the syringe plunger in aposition to be subsequently retracted to aspirate fluid, such ascontrast media, into the syringe for an injection procedure. In apreferred embodiment, the injector senses the mounting or installationof the syringe thereon and automatically advances the piston withoutoperator intervention to drive the plunger to the distal end of thesyringe. Of course, this feature would ordinarily be used only withempty syringes (as compared to preloaded or prefilled syringes) toprevent fluid from being expelled therefrom.

As discussed above, in a preferred embodiment, the injectors andinjector systems of the present invention may be adapted toautomatically differentiate between, for example, empty syringes andpreloaded syringes (via, for example, sensors 5512 a-d and sensors 5512a′-d′). Because preloaded syringes are empty syringes that have beenfilled with fluid and stored prior to an injection procedure, andfurther because operators, depending on the application or need, may ormay not preload empty syringes with fluid for storage prior to theinjection procedure, the injector may have difficulty differentiatingbetween empty, plunger-rearward syringes and preloaded syringes.

One possible arrangement to address this concern is to assemble theplunger-rearward syringes with their plungers located at positionsrearward of the maximum fill volume of the syringes. As can beappreciated, this arrangement will result in preloaded syringes havingtheir plungers located (after loading with fluid) at some position equalto or forward of the maximum fill volume of the syringes. In operation,after a syringe is placed on the injector and identified as an emptysyringe, the auto engage feature will drive the piston forward to engagethe syringe plunger. If the piston engages the syringe plunger at aposition rearward of the maximum fill volume of the syringe, theinjector will discern that a plunger-rearward syringe has been installedthereon and the auto advance feature will be enabled to drive theplunger to the distal end of the syringe to expel air therefrom and toplace the plunger in position for aspiration of fluid into the syringe.On the other hand, if the piston engages the syringe plunger at aposition equal to or forward of the maximum fill volume of the syringe,the injector will discern that a preloaded syringe has been installedthereon. Of course, when the injector determines that a preloadedsyringe has been installed thereon, the auto advance feature will not beenabled (i.e., to prevent the piston from advancing the plunger to thedistal end of the syringe, thereby expelling the preloaded fluid formthe syringe).

The “auto fill” or “auto load” feature allows an injector toautomatically retract a syringe plunger (i.e., by means of the injectorpiston) to draw in or aspirate a programmed amount of fluid, such ascontrast media, into the syringe. Preferably, the auto fill featureoccurs without operator intervention, thereby allowing the operator toperform other tasks (e.g., programming the scanner or injector,positioning the patient on the scanner table, catherizing the patient)while the syringe is being filled with the required amount of fluid. Ofcourse, this feature typically is not necessary for prefilled orpreloaded syringes, which already contain fluid therein.

In a preferred embodiment, the auto fill feature also includes a“trapped air reduction” feature to reduce the amount of air aspiratedinto the syringe during the fluid aspiration procedure. During anaspiration procedure facilitated by, for example, the auto fill feature,the injector piston retracts the syringe plunger to draw fluid into thesyringe. Often, for example, when the aspiration flow rate issufficiently great, air is aspirated into the syringe along with thefluid. To reduce the amount of air aspirated into the syringe, thetrapped air reduction feature reverses the motion of the injector piston(i.e., to slightly advance the injector piston) one or more times duringthe aspiration procedure. By reducing the amount of air aspirated intothe syringe during the fill operation, the quantity and size of airbubbles formed in the syringe, as well as the time required tosubsequently expel air from the syringe and connecting tube (i.e.,priming the system) are reduced, resulting in a lower probability of aninadvertent air injection.

The “auto prime” feature allows an injector to automatically prime thefluid path (i.e., syringe and connecting tubing) before an injectionprocedure. Preferably, the volume of fluid contained within a connectortubing used with a syringe is pre-programmed into the injector. Forexample, a 60′ low pressure connecting tubing (“LPCT”) provided byMedrad, Inc., the Assignee of the present application, for use with itsdisposable syringes typically holds approximately 2.78 ml of fluid.Alternately, the operator may manually program the fluid volumecontained within the connector tube into the injector.

As will become apparent, the auto prime feature may be functionallydependent, in certain respects, on the auto fill feature describedabove. When a syringe is filled with fluid (i.e., by means of the autofill feature), the injector automatically compensates for the connectortube by adding its corresponding fluid volume to the fluid volumedesired by the operator to be aspirated into the syringe for aninjection operation, which can be set forth as part of an injectionprotocol input by the operator. For example, if the operator desires tofill the syringe with 150 ml of fluid for an injection procedure, theauto fill feature will compensate for the connector tube fluid volume byautomatically adding 2.78 ml of fluid (e.g., for a 60′ LPCT), for atotal volume of 152.78 ml aspirated into the syringe. After the syringeis filed with fluid, the auto prime feature would then cause theinjector piston to advance the syringe plunger to the extent necessaryto expel air from the syringe and connector tube system, preferablywithout prompting by the operator. Once the auto prime function isconducted, fluid should be present at the patient end of the connectortube (i.e., the end that is connected to the catheter).

As can be appreciated, the auto prime feature may save operator time andreduce the amount of wasted fluid. By automatically compensating for thefluid contained within the connector tube, the operator does not have tovigilantly watch the progression of the fluid from the syringe throughthe connecting tube in order to stop the advancement of the pistonbefore a significant amount of fluid is discharged from the end of theconnector tubing. Also, because some operators of conventional injectorsadvance the piston quickly to lessen the time required to prime thesyringe and tubing system, often a significant amount of fluid will beexpelled from the end of the connector tubing before the operator stopsthe piston's advancement. If a sufficient amount of contrast isexpelled, the syringe may have to be re-filled (and the syringe andtubing system subsequently re-primed) to insure that it contains asufficient amount of fluid for the required injection procedure.

While the auto prime feature is preferably intended for use with emptysyringes that have been filled with fluid by an aspiration procedure onthe injector (i.e., non-prefilled and non-preloaded syringes), the autoprime feature could also be used with prefilled and preloaded syringes.

The “auto retract” feature allows an injector to automatically retractthe injector piston after a syringe is removed or disconnected from theinjector. At the end of an injection procedure, the injector piston andthe syringe plunger is typically located at the distal end of thesyringe. Therefore, as described above and in U.S. Pat. Nos. 5,383,858and 5,300,031 (both of which are incorporated herein by reference),after the syringe is disconnected from the injector, the injector pistonoften extends from the front of the injector (or within a pressurejacket attached to the front of the injector). Especially in the case ofplunger-rearward syringes, preloaded syringes and prefilled syringes,the piston usually must be retracted in order to mount a new syringeonto the injector for the next injection procedure. To save operatortime in retracting the piston, the auto retract feature automaticallyretracts the piston after the injector senses that the syringe has beenremoved therefrom (e.g., after an injection procedure) to place theinjector piston in position to accept a new syringe. If plunger-forwardsyringes are being used on the injector, the auto retract feature may bedeactivated to prevent unnecessary and/or redundant piston movements.The auto retract feature could be manually deactivated by the operatoror automatically by the injector. For example, when a plunger-forwardsyringe is installed on and identified by the injector, the injectorcould automatically initiate a default setting to deactivate the autoretract feature for subsequent syringes until an operator override isactivated or until the system detects the attachment of a prefilled,preloaded or plunger-rearward syringe. When the injector detects aprefilled or preloaded syringe, the system can compensate for anyresidual air remaining in the syringe by adjusting the amount of primingto be conducted. For example, if the prefilled syringe typicallycontains approximately 1.2 ml of air or “dead space” and is connected toa 60′ LPCT (accommodating approximately 2.78 ml of fluid), the injectorsystem would prime approximately 3.97 ml from the syringe and connectingtube system.

As will be appreciated, depending on operator need, the auto featuresdescribed above could be used independently or in conjunction with oneanother to facilitate injector use. For example, the auto featuresdescribed above could be used with a plunger rearward syringe in thefollowing manner. After an operator installs the plunger rearwardsyringe on an injector, the auto advance feature advances the syringeplunger to the distal end of the syringe (i.e., to expel air from thesyringe and to place the plunger into position to aspirate fluidthereinto). The auto fill feature subsequently aspirates a predeterminedamount of fluid into the syringe, based on the desired operator amountfor the injection procedure and, preferably, compensating for the fluidvolume of the connector tubing. The auto prime feature thenautomatically advances the injector piston and syringe plunger to removeair from the syringe and connecting tube system. Subsequently, after theinjection procedure is completed and the syringe is removed from theinjector, the auto retract feature retracts the injector piston to placethe injector in position for the next injection procedure with a plungerrearward syringe, a preloaded syringe or a prefilled syringe.

As another example, the auto features could be used with a prefilledsyringe or a preloaded syringe in the following manner. After anoperator places the prefilled syringe or preloaded syringe on theinjector, the auto engage feature advances the injector piston into thesyringe to mate or engage with the syringe plunger. The auto primefeature then advances the piston and plunger to expel air from andthereby prime the syringe and connector tubing system. Subsequently,after the injection procedure is completed and the syringe is removedfrom the injector, the auto retract feature retracts the injector pistonto place the injector in position for the next injection procedure witha plunger rearward syringe, a preloaded syringe or a prefilled syringe.

As yet another example, the auto features could be used with a plungerforward syringe in the following manner. After an operator places theplunger forward syringe on the injector, the auto engage featureadvances the injector piston into the syringe to mate or engage with thesyringe plunger. The auto fill feature subsequently aspirates apredetermined amount of fluid into the syringe, based on the desiredoperator amount for the injection procedure and, preferably,compensating for the fluid volume of the connector tubing. The autoprime feature then automatically advances the injector piston andsyringe plunger to remove air from the syringe and connecting tubesystem. Subsequently, after the injection procedure is completed and thesyringe is removed from the injector, the auto retract feature retractsthe injector piston (if, for example, the default setting to deactivatethe auto retract feature for plunger forward syringes has beenoverridden by the operator) to place the injector in position for thenext injection procedure with a plunger rearward syringe, a preloadedsyringe or a prefilled syringe. If new plunger forward syringes are tobe used with the injector (and the default setting to deactivate theauto retract feature for plunger forward syringes has not beenoverridden by the operator), then the auto retract feature will notoperate and the piston is left in its extended position for the nextsyringe.

The injectors and injector systems of the present invention may alsoinclude additional features complementary to one or more of the autofeatures described above to further enhance the usefulness of the autofeatures and to free operators to perform additional functions. Forexample, the injectors and injector systems of the present invention maybe provided with an attachment device for holding fluid sources, such asbottles or bags, during the auto fill function. By holding the fluidsource during the auto fill function, the need for the operator to holdthe fluid source during filling of the syringe is eliminated, therebyfreeing the operator for other activities preparatory to the injectionprocedure. Of course, the fluid source attachment device would providebenefit to the operator apart from the auto fill function. For example,if the auto fill feature were not available on a particular injector,the fluid source attachment device would still function to hold thefluid source during operator-enabled filling operations.

In addition, the injectors, syringes and injectors systems of thepresent invention may be provided with an attachment device for holdingthe patient end of the connector tubing during the priming function(e.g., auto prime or operator-enabled priming). By holding the patientend of the connector tubing, preferably in the vertical direction toprevent fluid from dripping out of the patient end, the connector tubingattachment device frees the operator for other activities preparatory tothe injection procedure. Of course, various other injector operations(injection protocol programming, check for air, etc.) are or may beconducted between the various auto functions.

A number of the above identified auto features (for example, autoloading and auto priming) and other injector features of the presentinvention are discussed in connection with a representative example ofinjector 5500 and graphical user interfaces for control thereof in, forexample, a computerized tomography (CT) environment. In a CTenvironment, a control unit (control room unit) for control of injector5500 is placed in a control room (see, for example, FIG. 128A), which isshielded from radiation used to produce the CT scan. Injector 5500 ispositioned within a scan room with the CT scanner and a scan roomcontrol unit (scan room unit) in communication with injector 5500 and incommunication with the control room unit. The scan room unit canduplicate some or all of the control features found on the control roomunit as known in the art. Moreover, the scan room unit can includeinjector control features in addition to those found on the control roomunit as known in the art. Other control units such as a handheld controlunit can be provided as known in the art.

In a typical procedure, the operator of the CT procedure first programsthe protocol for the injection procedure using the control room unit.Several screen captures of an embodiment of a graphical user interface(GUI) 6000 for the control room unit are illustrated in FIGS. 128Athrough 128D (which can, for example, be operated in the manner of atouch screen). See also, U.S. Pat. No. 6,339,718, the contents of whichare incorporated herein by reference. In this embodiment, the controlsystem of injector 5500 includes three modes of injection selectable bythe operator as illustrated, for example, in the interface screen ordisplay of FIG. 128B. The screen of FIG. 128B can, for example, bedisplayed upon activation of a modify switch or button 6005 on theinterface screen or display of FIG. 128A. These modes of operationinclude a mode for sequential injection from syringes 5900A and 5900B, amode for simultaneous injection from syringes 5900A and 5900B into asingle injection site and a mode for simultaneous injection fromsyringes 5900A and 5900B into different injection sites.

In the case of a sequential injection, a fluid can be injected from onlyone of syringe 5900A or 5900B at a time. For example, syringe 5900A cancontain contrast medium, while syringe 5900B can contain a flushingfluid such as saline, which can be sequentially injected into a patientusing a variety of protocols as known in the art. An example of a fluidpath for sequential injection is illustrated in FIG. 129A. In FIG. 129A,tubing from each of syringes 5900A and 5900B come together via aT-connector 6400 for fluid connection to the injection site on thepatient.

A plurality of phases of sequential injection can be entered usingcontrol room interface 6000. FIG. 128C, for example, illustrates asix-phase, sequential injection protocol in which 2 ml of saline fromsyringe 5900B is first injected at a flow rate of 4.0 ml/sec in a firstphase. The second phase is a hold phase in which injector 5500 holds theinjection until the user reactivates the injection, using, for example,the scanning room display start switch, hand control switch or othercontrol. In the third phase, 60 ml of fluid is injected from syringe5900A at a flow rate of 4.0 ml/sec. In the fourth phase, 60 ml of fluidis once again injected from syringe 5900A at a flow rate of 4.0 ml/sec.In the fifth phase, the injection is paused for 10 sec. In the sixth andfinal phase, 10 ml of saline is injected from syringe 5900B at a flowrate of 2.0 ml/sec.

During simultaneous injection into a single site (using for example thefluid path of FIG. 129A), syringe 5900A can, for example, be loaded orfilled with contrast medium, while syringe 5900B can, for example, beloaded with a diluent or flushing fluid such as saline. In this mode,contrast medium or other fluid in syringe 5900A can, for example, bediluted or mixed with fluid in syringe 5900B to a desired concentrationby simultaneous injection from syringe 5900A and 5900B as programmed bythe operator. For example, FIG. 128D illustrates a setup forsimultaneous injection of 50 ml of a mixture of 80% fluid from syringe5900A and 20% fluid from syringe 5900B with a flow rate of 5 ml/sec.Piston 5520 and piston 5520′ of injector 5500 will thus be advanced in acontrolled manner such that 40 ml of fluid from syringe 5900A and 10 mlof fluid from syringe 5900B will be simultaneously injected into asingle injection site over a period of 10 seconds.

In the case of a simultaneous injection to different injection sites(see FIG. 129B), syringe 5900A and syringe 5900B can, for example bothbe filled with the same injection fluid (for example, contrast medium).Injection of the contrast medium at two different sites, as opposed to asingle site, can, for example, enable delivery of a desired amount ofcontrast medium to a region of interest at a lower flow rate and a lowerpressure at each site than possible with injection into a single site.For example, half the contrast medium desired for delivery to apatient's P's heart can be injected into a vein on each of the patient'sP's arms (see FIG. 129B), rather than injection of the entire amountinto a single injection site on one of the patient's P's arm. The lowerflow rates and pressures enabled by simultaneous injection into multiplesites can, for example, reduce the risk of vascular damage andextravasation.

After setting the desired protocols at the control room unit in any ofthe above injection modes, the operator typically enters the scan roomfor final preparations of injector 5500 and/or final preparations of thepatient. In the embodiment of FIGS. 129A and 129B, the scan room unit ispart of or in incorporated in injector head 5500 with a control/displayGUI or interface 6100 positioned on an upper side of injector 5500.Incorporating the scan room unit into injector head 5500 can, forexample, reduce the use of space within the scan room as compared to aseparate control unit.

Control room interface 6000 preferably includes a lock protocol function6010, which can, for example, be a button, micro-switch or touch screenarea activated by the operator to “lock” the protocol. Subsequentediting of the injection protocol preferably deactivates protocolfunction lock 6010. Alternatively, activation of protocol lock 6010 canprevent editing of the set protocol until protocol lock 6010 isdeactivated. Activation and deactivation of protocol lock 6010preferably changes the state (for example, activates and deactivates,respectively) an indicator (for example, a light) 6110 on interface6100. When activated, indicator 6110 ensures the operator that anotherhas not altered the set protocols while the operator is in the scanroom. In that regard, editing of the set protocol is associated withdeactivation of protocol lock 6010, and deactivation of protocol lock6010 results in a change of state (for example, deactivation) ofindicator 6110. The protocol lock can, for example, lock out furtherprotocol editing and be password encoded for extra assurance thatundesired protocol changes are not entered.

After connection of empty syringes 5900A and 5900B to injector 5500, theconfigurations of syringes 5900A and 5900B are preferably sensed asdescribed above. After auto docking or auto engaging as well as autoadvancing preferably proceeds as described above, the injector system isready for filling of empty syringes 5900A and 5900B. In the embodimentof FIGS. 129A and 129B, syringes 5900A and 5900B are in fluid connectionwith sources or reservoirs of injection fluid, 6200 and 6300,respectively. For example, source 6200 can be a reservoir of contrastmedium, while source 6300 can be a reservoir of a flushing or dilutingfluid such as saline. A valve system, which can, for example, includecheck valves 6210 and 6310, can be provided to control fluid flow asknown in the art and to prevent cross contamination between patientswhen, for example, sources 6200 and/or 6300 are used with multiplepatients.

Auto loading and/or auto priming can begin automatically upon setting ofprotocols as described above. Alternatively, auto loading can bemanually initiated, at least in part, by the operator via activation ofan auto load switch 6120 as well as fill switches or buttons 6122 and6124 for each of syringes 5900A and 5900B, respectively, on scan roomunit interface 6100. A display area 6130 of interface 6100 can, forexample, include a numeric display as well as a graphical display of theamount of fluid in each of syringes 5900A and 5900B. Different colorscan be used to denote the different syringes and the different fluidstherein.

In the example of simultaneous injection of 50 ml of a mixture of 80%contrast medium from syringe 5900A and 20% saline from syringe 5900Binto a single injection site, the steps of auto loading, auto primingand injection are described in connection with FIGS. 128D through 128J.In FIGS. 128D and 128E, display area 6130 as well as a display area 6030of control unit interface 6000 indicate that auto loading has not yetbeen initiated. Each of syringes 5900A and 5900B are indicated to beempty (0 ml volume). FIG. 128F illustrates display area 6130 afteractivation of the auto load switch. The numeric portion of the displayindicates that 14 ml of saline will be loaded into syringe 5900B, while41 ml of contrast medium will be loaded into syringe 5900. For thetubing set used in the example of FIGS. 128D through 128J, 4 ml ofsaline and 1 ml of contrast are required to prime the tubing. Uponconfirmation/acceptance of the fill volumes, the operator activates eachof fill switches or buttons 6122 and 6124 to begin loading of contrastand saline into syringes 5900A and 5900B, respectively. Upon completionof loading, display area 6130 appears as illustrated in FIG. 128G. Uponactivation of an auto prime switch or button 6140, 1 ml of contrast isinjected from syringe 5900A and 4 ml of saline are injected from syringe5900B to prime the fluid path and tubing set. The tubing can now beconnected to a patient catheter. Display 6130 now appears as illustratedin FIG. 128H, wherein 40 ml of contrast are indicated to be presentwithin syringe 5900A and 10 ml of saline are indicated to be present insyringe 5900B.

Syringes 5900A and 5900B are now in a state to commence injection.Preferably, injector 5500 requires the operator to perform a check forair in the fluid path as known in the art. In that regard, the injectorsystem can prevent injection until an air check confirmation button orswitch 6150 on scan room unit interface 6100 is activated. After arminginjector 5500 by, for example, activating an arm switch or button oninterface 6000 or a similar arm switch or button 6150 on interface 6100,the injection can be initiated. As know in the art, arming the injectorcan initiate a number of self or internal tests and state checks toensure that injector 5500 is ready for injection.

FIG. 1281 illustrates the state of display area 6130 half way throughthe injection procedure, while FIG. 128J illustrates the state ofdisplay area 6130 upon completion of the injection procedure. Thegraphical representation and numeric data of display area 6130 can alsobe reflected in similar display area 6030 of interface 6000. As seen inthe representative example of FIGS. 128D through 128J, the injectorsystem of the present invention provides for a wide range of injectedcontrast and other fluid concentrations adjusted during injectionthrough appropriate loading of syringes 5900A and 5900B with respectivefluids, and appropriate control of the simultaneous injection thereofinto a single site. Moreover, the concentration of contrast and otherfluids can be readily varied, adjusted or changed during an injectionprocedure if desired for a particular procedure.

The foregoing description and accompanying drawings set forth thepreferred embodiments of the invention at the present time. Variousmodifications, additions and alternative designs will, of course, becomeapparent to those skilled in the art in light of the foregoing teachingswithout departing from the scope of the disclosed invention. Forexample, the respective mating connection and release mechanisms on theinjectors and the syringes described above may be interchanged. Thescope of the invention is indicated by the following claims rather thanby the foregoing description. All changes and variations that comewithin the meaning and range of equivalency of the claims are to beembraced within their scope.

1. An injector system for injecting fluid from at least one syringemounted thereon, the syringe having a plunger slidably disposed therein,the injector system comprising: a housing; at least one drive member atleast partially disposed within the housing and operable to engage theplunger of the syringe; a controller in operative connection with thedrive member; at least one syringe retaining mechanism associated withthe housing, the syringe retaining mechanism adapted to releasablyengage the syringe; and a first sensing pin positioned at a forward endof the drive member and extending forward of a forward surface of thedrive member to sense contact of the first sensing pin with an innersurface the syringe plunger upon forward advancement of the drive memberto engage the syringe plunger prior to contact of the forward surface ofthe drive member with the syringe plunger, the first sensing pin beingforced rearward upon with contact with the inner surface of the syringeplunger without causing forward movement of the syringe plunger, therearward motion of the first sensing pin causing data of proximity ofthe inner surface of the syringe plunger and the forward surface of thedrive member to be transmitted to the controller before contact of theforward surface of the drive member with the inner surface of thesyringe plunger to control forward advancement of the drive member,wherein the forward surface of the drive member is shaped to conform tothe inner surface of the plunger.
 2. The injector system of claim 1wherein the first sensing pin is biased in a forward extended positionand is forced rearward to impinge upon a sensor in communicativeconnection with the controller when contact with the syringe plunger ismade during advancement of the drive member.
 3. The injector system ofclaim 1 wherein the first sensing pin is positioned forward of the atleast one syringe retaining mechanism.
 4. The injector system of claim1, further comprising: a second drive member at least partially disposedwithin the housing and operable to engage a plunger of a second syringe;a second syringe retaining mechanism associated with the housing, thesecond syringe retaining mechanism adapted to releasably engage thesecond syringe; and a second sensing pin positioned at a forward end ofthe second drive member to sense contact of the second sensing pin withthe second syringe plunger.
 5. The injector system of claim 4, furthercomprising: a source of a first injection fluid in fluid connection withthe first syringe; and a source of a second injection fluid in fluidconnection with the second syringe.
 6. The injector system of claim 1,further comprising a sensing system to sense when a syringe is attachedto the retaining mechanism.
 7. The injector system of claim 6 whereinthe sensing system further senses the syringe configuration.
 8. Theinjector system of claim 6 wherein the drive member automatically movesforward upon connection of a syringe to the retaining mechanism toengage the syringe plunger.
 9. The injector system of claim 8 whereinforward movement of the drive member is stopped upon engagement with thesyringe plunger but before the plunger is moved forward.
 10. Theinjector system of claim 1 wherein the forward surface of the drivemember is generally conical and the sensing pin is generally at thecenter of the conical forward surface of the drive member.
 11. Theinjector system of claim 10 wherein the inner surface of the syringeplunger is the inner surface of an elastomeric plunger cover.
 12. Theinjector system of claim 11 wherein the syringe plunger comprises anannular base connected to the plunger cover, the forward surface of thedrive member passing through the annular base upon advancement of thedrive member to engage the syringe plunger.
 13. An injector systemcomprising: a housing; a drive member at least partially disposed withinthe housing and operable to engage a plunger of a syringe mounted on thehousing; a controller in operative connection with the drive member; anda sensing mechanism comprising a movable element disposed on a forwardend of the drive member and extending forward of a forward surface ofthe drive member, the sensing mechanism adapted to determine when themovable element makes contact within an inner surface of the syringeplunger upon forward advancement of the drive member to engage thesyringe plunger prior to contact of the forward surface of the drivemember with the syringe plunger, the movable element being forcedrearward upon with contact with the syringe plunger without causingforward movement of the syringe plunger, the rearward motion of themoveable element causing data of proximity of the inner surface of thesyringe plunger and the forward surface of the drive member to betransmitted to the controller before contact of the forward surface ofthe drive member with the inner surface of the syringe plunger.
 14. Theinjector system of claim 13 wherein the movable element is a movable pinand the sensing mechanism further comprises a sensor in communicativeconnection with the controller.
 15. The injector system of claim 14wherein the sensor is an optical sensor.
 16. The injector system ofclaim 14 wherein the movable pin is biased in a forward extendedposition and is forced rearward to impinge upon the sensor when contactwith the syringe plunger is made during advancement of the drive member.17. The injector system of 16 wherein the movable pin is biased in aforward extended position by a spring.
 18. The injector system of claim13, further comprising a syringe sensing system adapted to determinewhen a syringe is mounted on the housing.
 19. The injector system ofclaim 18 wherein the drive member automatically moves forward to engagethe syringe plunger upon mounting of a syringe on the housing.
 20. Theinjector system of claim 19 wherein forward movement of the drive memberis stopped upon engagement with the syringe plunger but before thesyringe plunger is moved forward.
 21. An injector system comprising: ahousing; a syringe retaining mechanism associated with the housing forreleasably engaging a syringe; a drive member at least partiallydisposed within the housing and operable to engage a plunger of thesyringe; a controller in operative connection with the drive member; asyringe sensing system operably associated with the syringe retainingmechanism, the syringe sensing system adapted to determine when thesyringe is releasably engaged by the syringe retaining mechanism; and aplunger sensing mechanism comprising a movable element disposed on aforward end of the drive member and extending forward of a forwardsurface of the drive member, the plunger sensing mechanism beingoperable to sense when the moveable element contacts an inner surface ofthe plunger upon forward advancement of the first drive member to engagethe plunger prior to contact of the forward surface of the drive memberwith the plunger, the movable element being forced rearward upon contactwith the plunger without causing forward movement of the plunger, therearward motion of the movable element causing data of proximity of theinner surface of the plunger and the forward surface of the drive memberto be transmitted to the controller before contact of the forwardsurface of the drive member with the inner surface of the plunger. 22.The injector system of claim 21 wherein the movable element is a movablepin and the plunger sensing mechanism further comprises a sensor incommunicative connection with the controller, the movable pin beingbiased in a forward extended position and being forced rearward toimpinge upon the sensor when contact with the syringe plunger is madeduring advancement of the drive member.
 23. The injector system of claim22 wherein the sensor is an optical sensor and the movable pin isspring-biased in a forward extended position.
 24. An injector systemcomprising: a housing; a first drive member at least partially disposedwithin the housing and operable to engage a plunger of a first syringemounted on the housing; a second drive member at least partiallydisposed within the housing and operable to engage a plunger of a secondsyringe mounted on the housing; a controller in operative connectionwith the first drive member and the second drive member; a firstmechanism comprising a first movable element disposed on a forward endof the first drive member and extending forward of a forward surface ofthe first drive member, the first mechanism being adapted to sense whenthe first movable element contacts an inner surface of the first syringeplunger upon forward advancement of the first drive member to engage thefirst syringe plunger prior to contact of the forward surface of thefirst drive member with the first syringe plunger, the first movableelement being forced rearward upon contact with the first syringeplunger without causing forward movement of the first syringe plunger,the rearward motion of the first movable element causing data ofproximity of the inner surface of the first syringe plunger and theforward surface of the first drive member to be transmitted to thecontroller before contact of the forward surface of the first drivemember with the inner surface of the first syringe plunger; and a secondmechanism comprising a second movable element disposed on a forward endof the second drive member extending forward of a forward surface of thesecond drive member, the second mechanism being adapted to sense whenthe second movable element contacts an inner surface of the secondsyringe plunger upon forward advancement of the second drive member toengage the second syringe plunger prior to contact of the forwardsurface of the second drive member with the second syringe plunger, thesecond movable element being forced rearward upon with contact with thesecond syringe plunger without causing forward movement of the secondsyringe plunger, the rearward motion of the second movable elementcausing data of proximity of the inner surface of the second syringeplunger and the forward surface of the second drive member to betransmitted to the controller before contact of the forward surface ofthe second drive member with the inner surface of the second syringeplunger.